Công cụ trực tuyến miễn phí 1Stop Tools

Free online word counter. Instantly count words, characters, sentences, paragraphs, and reading time. No upload — your text stays in your browser.

Free online character counter — counts letters, digits, punctuation, whitespace, and total characters with full unicode support.

Remove duplicate lines from text or lists. Case-insensitive and trim options. Browser-based, free, no uploads.

Sort lines alphabetically, by length, or numerically. Ascending or descending, case-insensitive, with empty-line removal.

Case Converter — Switch text between UPPERCASE, lowercase, Sentence case, and tOGGLED cASE. Runs entirely client-side inside your browser.

Find and Replace — Replace any pattern in your text — exact match or regex, case-sensitive or not. Runs entirely client-side inside your browser.

Base64 Encode / Decode — Convert any text to Base64, or decode Base64 back to readable text. Full unicode support.

Lorem Ipsum Generator — Generate Lorem Ipsum placeholder text — pick words, sentences, or paragraphs and copy the result.

Password Generator — Generate a strong, random password. Tunable length, character classes, and ambiguous-character exclusion. Nothing leaves your browser.

URL Encoder / Decoder — Encode or decode URL strings — single component or full URL — with proper percent-encoding.

Extract Emails — Paste any text — emails, logs, web pages — and get back a clean list of email addresses. Runs entirely client-side inside your browser.

Extract URLs — Get a clean list of every URL in a block of text — http, https, and www. style addresses. Runs entirely client-side inside your browser.

Hash Generator — Hash any text with MD5, SHA-1, SHA-256, SHA-384, or SHA-512 — all client-side via Web Crypto.

Upside-Down Text — Generate ¡uʍop-ǝpısdn text using Unicode look-alike characters. Paste it anywhere that accepts Unicode.

Stylize Text (Bold, Italic, Mono, Wide) — Turn plain text into Unicode 𝐁𝐨𝐥𝐝, 𝐼𝑡𝑎𝑙𝑖𝑐, 𝙼𝚘𝚗𝚘, Sᴍᴀʟʟ Cᴀᴘs, or Ｗｉｄｅ characters — pastable anywh...

Strip HTML Tags — Paste HTML and get back the plain text content — tags removed, entities decoded, scripts and styles stripped.

Random Line Picker — Paste a list and pick random lines — for raffles, decisions, sampling, or quick games. Runs entirely client-side inside your browser.

Add Prefix / Suffix to Lines — Add the same prefix or suffix (or both) to every line of your text. Runs entirely client-side inside your browser.

Trim Whitespace — Strip leading and trailing whitespace from text — per-line, full-text, or with extra-space collapsing.

Count Occurrences — Count how many times a word, phrase, or regex appears in your text. Runs entirely client-side inside your browser.

HTML Editor (WYSIWYG) — A simple in-browser WYSIWYG editor — format with the toolbar, paste rich text from Word or web pages, and copy the resulting HTML.

JSON Formatter / Validator — Format, minify, or validate any JSON in your browser. Choose indent style and see error details for invalid input.

Markdown to HTML — Convert Markdown to HTML with live side-by-side preview. Supports headings, lists, links, images, code blocks, blockquotes, and empha...

Text Diff / Compare — Compare two blocks of text and see exactly what changed — added lines in green, deleted in red, unchanged in gray.

UUID Generator — Generate UUIDs in bulk — v4 (random) or v7 (time-ordered). Optional uppercase and braces. Runs entirely client-side inside your browser.

Keyword Density Analyzer — Analyze keyword frequency and density in any text. Filter out common words, set minimum length, and see the top N.

JWT Decoder — Paste a JWT and see the header, payload, expiry, and signature parts decoded. Everything happens in your browser.

CSV ↔ JSON — Convert tabular data between CSV and JSON. Header row detection, custom delimiter, quoted-field-with-comma support.

Image Resize — Resize any image to exact pixel dimensions — keep the aspect ratio or stretch. Output as PNG, JPEG, or WebP.

Image Compressor — Compress images to dramatically smaller files — adjust quality, cap maximum width, and see how much you saved.

Image Crop — Crop any image by dragging a rectangle over the area you want to keep. Pixel-precise, downloadable as PNG, JPEG, or WebP.

Image Format Converter — convert any image between PNG, JPEG, and WebP. Tune quality for JPEG/WebP output. Runs entirely in your browser.

PDF Merge — Combine multiple PDF files into a single document — in the order you select them. Everything happens in your browser.

PDF Rotate Pages — Rotate PDF pages 90°, 180°, or 270° — apply to all pages or specific ones like 1,3-5. Runs entirely client-side inside your browser.

Image to PDF — Pack one or more images into a single PDF — each image becomes a page. A4, Letter, Legal, or fit-to-image page sizes.

Random String Generator — Produce one or many cryptographically random strings — pick the length, the character classes, and how many you need.

Compare Two Lists — Drop two newline-separated lists into the boxes and instantly see what is shared, what is unique to each, and the merged union.

Image Rotate — Rotate any image — 90°/180°/270° quick presets, or any arbitrary angle. Canvas is resized so nothing is clipped.

Image Filters — Apply CSS-grade filters to any image — grayscale, sepia, blur, brightness, contrast, saturation, hue-rotate, invert. Live preview as you...

PDF Split — Split a PDF into multiple files — by page ranges like 1-3,5,7-10, by every N pages, or just extract one combined subset.

PDF Compress — Light, lossless PDF compression — re-saves with object streams and tighter encoding. Best for documents with redundant structure.

PDF Watermark — Stamp every page of a PDF with a text watermark — perfect for 'DRAFT', 'CONFIDENTIAL', or your name across distributed copies.

Regex Tester — Test JavaScript regular expressions live — see matches highlighted in your text and captured groups in a list.

Color Converter — Convert between HEX, RGB, HSL, and RGBA — pick a color or type any format and the others update live.

JSON Diff — Compare two JSON values structurally — see exactly what was added, removed, or changed, with full key paths.

Cron Expression Builder — Edit a 5-field cron expression and see plain-English description plus the next 5 fire times in your local timezone.

CSV Viewer — Paste any CSV — comma, semicolon, tab, or pipe-delimited — and see it as a clean, scrollable table.

CSV Filter — Filter CSV rows by any column — contains, equals, regex match, numeric compare, empty / not-empty.

CSV Deduplicate — Remove duplicate rows from a CSV. Dedupe on the full row, or just on selected key columns (e.g. dedupe by email).

CSV Stats — Per-column statistics for any CSV — total count, non-empty, unique values, plus numeric min/max/mean/sum for any column with numbers.

Count Duplicates in List — Paste any list — one item per line — and get back each unique value with how many times it appeared, sorted by frequency.

Privacy Policy Generator — Generate a privacy policy template for your website — fill in your company info, pick what data you collect, choose GDPR/CCPA...

Terms of Service Generator — Generate a terms-of-service template — pick the optional sections relevant to your service (payments, refunds, user content...

Robots.txt Generator — Build a robots.txt — allow / disallow rules per user-agent, optional crawl-delay, and sitemap URL.

Meta Tag Generator — Generate SEO meta tags, Open Graph tags, and Twitter Card tags for any page — with a live Google search-result preview and length w...

Color Palette Generator — Pick a base color and generate a harmony palette — complementary, analogous, triadic, tetradic, split-complementary, monochrom...

CSS Gradient Generator — Build linear, radial, or conic CSS gradients visually. Add unlimited color stops, drag the angle, see the live preview, and cop...

Markdown Table Generator — Build Markdown tables with a visual cell editor — set rows/columns, click to edit any cell, pick alignment, or import from CSV.

Email Signature Generator — Build an email signature with your name, title, contact info, social handles, and optional logo. Three style presets: modern...

DOCX to Text — Drop a .docx Word document and get back its plain text — no formatting, just the content. Runs entirely in your browser.

DOCX to HTML — Convert a .docx Word document to clean, semantic HTML — headings, bold/italic, lists, links, and tables are all preserved.

XLSX to CSV — Convert any Excel sheet to CSV — pick a delimiter, pick a sheet, or zip all sheets at once. Runs in your browser, no upload.

XLSX to JSON — Convert any Excel sheet to JSON — array of objects keyed by header row, or array of arrays with no header.

Excel Unlocker — Remove edit protections, sheet locks, and workbook structure restrictions from Excel files. Runs entirely in your browser using the XML...

CSV to XLSX — Wrap a CSV file (or pasted CSV) into a single-sheet Excel .xlsx file. Pick the delimiter, sheet name, and output filename.

PPTX to Text — Extract visible text and speaker notes from a .pptx PowerPoint deck — slide by slide, with optional Slide N headers.

CSV Studio — Drop a CSV file (or load 100-row demo data) and explore it like a power tool: filter rows, sort by multiple columns, bulk-update cells, vis...

QR Code Generator — Generate a QR code for any text or URL — pick foreground/background colors, size, margin and error-correction level. Download as SVG...

PDF to Text — Drop a PDF and extract every text run from every page — with optional page headers and line-break preservation. Powered by Mozilla's pdf.j...

Color Contrast Checker — Pick a foreground and background color and instantly see the WCAG 2.1 contrast ratio with pass/fail badges for AA and AAA, norm...

SQL Formatter — Paste any SQL query and get it formatted with proper indentation, keyword casing, and clause breaks. Supports 10 dialects including Post...

YAML Formatter — Paste any YAML and format it cleanly — pick indent width and line wrap, optionally sort keys. Also validates YAML syntax and converts b...

JSON to TypeScript — Paste a JSON payload and instantly get TypeScript interfaces (or type aliases) describing its shape. Optionally mark all properties...

Cron Visualizer — Paste any 5-field cron expression and instantly see: a plain-English description, a field-by-field breakdown, and the next 10 schedule...

DOCX to PDF — Drop a .docx Word document and convert it to a clean, paginated PDF. Pick the page size, font size, and optional header/page numbers. Runs...

XLSX to PDF — Convert any Excel workbook to a PDF — each sheet renders as a landscape page with grid borders, scaled columns, and an optional bold heade...

PPTX to PDF — Drop a .pptx and convert it to a clean PDF — each slide becomes a 16:9 landscape page with a bold title and bullet body. Speaker notes opt...

Line Filter — Stack multiple filters to strip unwanted lines from a block of text. Each filter says "remove if line contains X", "…does NOT contain Y", ...

PDF Reorder Pages — Reorder pages of any PDF using up/down/top/bottom buttons. Remove unwanted pages on the spot. Save the reorganized PDF without uploa...

PDF Remove Pages — Strip specified pages out of a PDF. Use single page numbers and ranges (e.g. <code>2,5-8</code>) — everything else is kept and saved ...

PDF Metadata Editor — Edit the title, author, subject, keywords, creator and producer fields of a PDF. Or tick "Strip all" to fully clear the metadata b...

PDF N-up — Shrink and tile multiple PDF pages onto a single sheet — 2-up, 4-up, 6-up or 9-up. Useful for printing handouts and saving paper. Pick output...

PDF Image Stamp — Drop a PDF and an image (PNG or JPEG) — the image is overlaid on each page at the position, size and opacity you choose. Great for add...

PDF Resize Pages — Convert every page of a PDF to a new size — A4 ↔ Letter ↔ Legal ↔ A3 ↔ A5 ↔ custom. Content can either stretch to fit, or scale with ...

PDF Header & Footer — Add text headers and/or footers to every page of a PDF. Use a current-page placeholder (the literal characters open-brace n close-...

PDF Insert Blank Pages — Insert blank pages into a PDF — after every page, after odd pages only (for proper duplex printing), before specific pages, or ...

App Icon Generator — Upload one 1024×1024 (or larger) image and instantly get every icon size required by iOS, Android, Google Play and the App Store — ...

Mobile Wallpaper Generator — Drop one image and get it auto-resized to every common phone, tablet, and desktop wallpaper resolution — iPhone 15 Pro Max,...

Open Graph Image Generator — Generate 1200×630 Open Graph cards, Twitter / LinkedIn social images, square Instagram-style images, or 9:16 story cards. D...

Markdown to PDF — Paste Markdown, get a clean, paginated PDF — headings sized by level, bullet/numbered lists, blockquotes, code blocks with a light gre...

Convert HTML to PDF — open in a print preview for high-fidelity output, or download a smaller text-only PDF. Browser-based, no upload.

PDF Crop Margins — Trim white margins from a PDF — independent control for top, bottom, left, right. Use percentage trims (works on any page size) or ab...

PDF Signature — Draw your signature with the mouse or your finger on a signature pad, or upload an image of an existing signature, and stamp it onto a P...

PDF Protect — Encrypt your PDF document with a user password and customize editing, printing, and copying permissions entirely in your browser.

PDF Unlock — Remove password protection from your encrypted PDF documents. Simply enter the password, verify the file contents, and download a decrypted...

EPUB to Text — Drop an .epub file and extract the plain text of every chapter in spine order. Optional chapter headers. Useful for searching, summarizin...

EPUB to HTML — Drop an .epub and get all chapters merged into one clean HTML document — wrap as standalone, optionally strip inline styles and class nam...

YouTube Thumbnail Maker — Build YouTube thumbnails — 1280×720 with a bold title overlay, optional background image, theme presets (bold yellow, red arro...

Instagram Carousel Slicer — Slice one wide image into 2 to 10 Instagram carousel slides — square, 4:5 portrait (recommended), or 9:16 story. Pick slice ...

Discord / Slack Emoji Optimizer — Resize and auto-compress images to fit emoji upload limits — Discord (≤256 KB), Discord Nitro animated (≤512 KB), Slac...

GitHub Badge Maker — Generate Shields.io-style SVG badges for any GitHub README. Pick label, value, colors and one of four styles (flat, flat-square, fo...

Audio Trim — Trim audio to a specific start–end range with optional fade in/out. Decodes any browser-supported format (MP3, WAV, OGG, M4A, FLAC) and exp...

Audio Normalize — Boost or attenuate audio to a target loudness — peak (max amplitude) or RMS (average energy). Exports a lossless WAV. Useful when mixi...

PDF to Image — Render each PDF page to PNG, JPEG or WebP at a scale you choose (1× = 72 DPI, 4× = 288 DPI). Powered by pdf.js running locally in your br...

Image OCR (Text from Image) — Drop a screenshot, scan, or photo and extract the text inside — entirely in your browser via Tesseract.js. 10 languages in...

WebP / AVIF Batch Converter — Bulk-convert images to WebP or AVIF in one click — 30–80% smaller than the original PNG/JPEG. Optional max-dimension resiz...

Convert a CSV to SQL INSERT statements for MySQL, PostgreSQL, SQLite or MS SQL. Optional CREATE TABLE, multi-value INSERT mode.

JSON to CSV — Convert any JSON array (of objects or arrays) — or even a single object — into clean CSV. Tick the Flatten option to expand nested objects...

JWT Encoder / Signer — Build and sign a JWT — pick HS256 / HS384 / HS512, paste a header and payload (JSON), provide your secret, get a signed token. Us...

Base32 / Base58 Encoder &amp; Decoder — Encode and decode Base32 (RFC 4648), Base32-hex, and Base58 (Bitcoin / IPFS). Sister tools to our Base64 encoder.

Lorem Markdown Generator — Generate placeholder Markdown for testing CMS templates, blog layouts, documentation themes — with headings, lists, code bloc...

MIME Type Lookup — Type a file extension (or filename) and get the proper <code>Content-Type</code> header value. Reverse lookup too — type a MIME type ...

PDF Visual Signer — The richest PDF signing flow on 1Stop Tools — upload your PDF, see each page rendered live, click or drag a rectangle to choose where ...

Image Signer — Place a signature anywhere on an image — perfect for signing artwork, photos, screenshots, or scanned documents that aren't PDFs. Draw wi...

PDF Text Stamp — Add a preset (APPROVED, DRAFT, CONFIDENTIAL, REVIEWED, PAID, VOID, ORIGINAL, COPY, URGENT) or custom text stamp across every page — box...

JSON to Go Struct — Paste a JSON sample and get matching Go struct definitions — with optional <code>json:"..."</code> tags, <code>omitempty</code>, and...

JSON to JSON Schema — Paste any JSON sample and get a JSON Schema describing its shape — useful for API documentation, request/response validation, and ...

JSON to Zod Schema — Paste JSON and get a ready-to-use <code>z.object({...})</code> Zod schema plus the inferred TypeScript type.

HTML to Markdown Converter — Paste any HTML snippet — from a blog post, a CMS export, or a webpage — and get clean Markdown ready for static site genera...

WhatsApp Link Generator — Build a <code>wa.me</code> click-to-chat link — enter an international phone number and an optional pre-filled message. Get th...

Image Merger — Drop or paste multiple images, choose a layout (vertical, horizontal, or grid), and download a single merged image. All in your browser —...

Food Macros Calculator — Determine your optimal daily calorie requirements and macronutrient breakdown for fat loss, maintenance, or muscle gain.

Micros & Vitamins Calculator — Check recommended daily allowances (RDAs) for major vitamins and minerals tailored to your age, biological gender, and li...

Training Volume Calculator — Log your exercises and sets to calculate your weekly workout volume load per muscle group and compare it against muscle-bui...

Free online audio pitch shifter and speed changer. Shift pitch up or down in semitones, slow down or speed up playback rate client-side.

Free online audio reverser. Upload any audio track and reverse the audio playback locally in your browser. Download reversed WAV losslessly.

Text Compare — Compare two texts side-by-side to highlight line and character differences. Ideal for developers, writers, and editors.

App Store Screenshot Generator — Create high-fidelity App Store and Google Play screenshots. Put your screens into sleek device mockups with gradients a...

Free online Ohm's Law calculator. Calculate voltage (volts), current (amps), resistance (ohms), and power (watts) with any two known values.

Free online electricity cost calculator. Estimate daily, monthly, and yearly power consumption in kWh and calculate energy bills based on your local.

Free online resistor calculator. Calculate resistor color codes (4 and 5 bands) and series/parallel equivalent resistance values instantly.

Code Diff & Merge — Compare two code snippets side-by-side. View additions and deletions with syntax highlighting, and merge changes interactively with ...

Data Format Converter — Convert between structured data formats instantly. Parse and serialize JSON, YAML, TOML, and XML with configurable indentation a...

Image Background Remover — Erase backgrounds from images automatically or manually. Choose between border color detection, color keying, or brush erasin...

PDF to Word — Convert PDF documents to editable Microsoft Word (.docx) files. The entire conversion happens locally in your browser — your files are nev...

PDF to Excel — Convert PDF tables to editable Microsoft Excel (.xlsx) spreadsheets. Detects columns automatically or lets you select delimiters, process...

Video Compressor — Resize and compress video files client-side. Adjust dimension scales and encoder bitrates to decrease file size.

Video Watermarker — Overlay text or image watermarks onto video files client-side. Drag to reposition and render in real-time.

Audio Waveform Editor — Import audio files to analyze amplitude profiles. Trim start and end offsets, add fade curves, and export to WAV format.

JSON Schema Builder — Build JSON validation models visually. Configure properties, toggle required attributes, and instantly copy JSON Schema, Zod code,...

Regex Explainer — Deconstruct regular expressions. Analyze quantifiers, capture groups, sets, boundaries, and flags with clear explanations.

Base64 Inspector — Analyze and validate Base64 content. Inspect MIME headers, calculate overhead size, preview file assets, and download decoded binary ...

Image Watermark Remover — Brush over watermarks, timestamps, or logos to erase them using client-side smart texture inpainting. Processed fully locally ...

Free online audio studio editor. Trim, fade, normalize, pitch-shift, reverse, change speed, and detect BPM of audio files 100% in your browser.

SQLite Studio & Viewer — Explore, query, and convert SQLite databases in your browser. Runs entirely client-side using WebAssembly database execution.

EPUB Studio — An all-in-one workstation to unpack EPUB ebooks, modify metadata fields, edit chapter contents, and export to TXT, MD, HTML, RTF, and PDF ...

EPUB Ebook Reader — An interactive, client-side EPUB viewer. Drop your ebook file to browse chapter Table of Contents, customize reading themes, and rea...

Free online code minifier. Compress HTML, CSS, and JavaScript code instantly in one place. Removes comments, whitespace, and formatting to optimize speed.

Free online moment resistance calculator for reinforced concrete slabs. Calculate ultimate design moment resistance (Mu) using rebar size, spacing.

Build a hyperlinked digital planner PDF for GoodNotes & Notability — pick year, sections, theme and iPad size, then download. Free, in your browser.

Process multiple images at once — resize, compress, convert format or add a watermark to all. Download as a ZIP. Free, all in your browser.

Real-time speech-to-text via browser speech recognition. Live transcription, continuous mode, language picker. Chrome/Edge only. Private — no upload.

Stamp text watermarks onto PDF pages: tile or center diagonal. Adjust font, opacity, rotation, color. Preview before download. Private, no upload.

Write HTML, CSS, JS in tabbed editors with live iframe preview. Auto-run, download as HTML file. Preloaded counter app sample. No server — pure browser.

Get ISO week number for any date. Week start/end, Hijri date beside Gregorian, day of year, mini calendar. Monday, Sunday, or Saturday week starts.

Optimize linear cuts: bars, pipes, beams, timber. FFD algorithm minimizes waste with visual layout. Supports blade kerf, bulk quantities. Free, private.

Optimize 2D sheet cuts: plywood, MDF, drywall, panels. Shelf algorithm with 90-degree rotation. Visual layout with kerf. Free & private in your browser.

Optimize steel bar and rebar cutting for construction. 12m default stock, FFD algorithm minimizes scrap. Visual layout, kerf support, bulk quantities.

Calculate tiles needed for floor or wall. Enter tile size, grout gap, area to get count, boxes, cost & visual grid layout. Free, private, no sign-up.

Calculate grout for tiling. Enter tile size, gap & area to get volume in kg/liters. Sanded, unsanded & epoxy grout supported. Free private tool.

Calculate paintable wall area for rooms. Subtract doors, windows & custom openings. Per-room breakdown with layout view. Free private tool.

Break overwhelming tasks into tiny micro-steps. Progress tracker, time estimates, stuck-button for sub-steps. Free ADHD-friendly productivity tool.

Virtual body doubling for ADHD focus. Set a timer with a named partner, get encouraging messages, and track your focus sessions. Free, private, no sign-up.

Build a personalized dopamine menu with starters, mains, sides, and desserts. Healthier alternatives to doom-scrolling. Free ADHD-friendly tool, private.

Track estimated vs actual task times. Visual bar charts show time blindness patterns with gentle buffer suggestions. Free ADHD-friendly tool, private.

Free online audio format converter. Convert between WAV, MP3, OGG, M4A, FLAC, and AAC directly in your browser. No upload — fully client-side with Web Audio API.

Download any public Instagram profile photo in full HD resolution. Enter a username or profile URL — no login required. Uses Instagram's public oEmbed API.

Extract direct image, video, and audio URLs from Instagram, Twitter/X, TikTok, YouTube, Facebook, Reddit, Pinterest, Vimeo, and SoundCloud post links.

Extract direct video URLs from any webpage. Finds video tags, streaming manifests (m3u8/mpd), iframe embeds, and poster images. Paste a URL or HTML source.

Free online Markdown editor with live preview, toolbar, GFM tables, RTL direction support for Arabic, Persian, Urdu, Hebrew. Download as HTML or Markdown. No signup.