All Free Online Tools | 3sec

PDF, Image, and Media Tools

Use these tools for quick file cleanup, image compression, PDF work, thumbnails, and privacy checks before sharing. Most processing happens in the browser; review quality, page order, and redaction before downloading.

Developer, SEO, and GEO Tools

JSON, Regex, JWT, Hash, Schema, llms.txt, and AI crawler tools help with debugging, structured data, and making pages easier for search engines and AI assistants to understand.

Calculators and Everyday Tools

Finance, date, time, health, and everyday utilities are built for fast estimates and planning. For filing, payments, medical decisions, or contracts, compare the result with official sources or professional advice.

QR Code Generator

Generate QR Codes for URLs, WiFi, vCards, or text. Download as PNG.

Count characters, words, lines, and paragraphs in real time.

Image Compressor

Compress JPG, PNG, and WebP images in your browser. Process multiple files at once.

Resize images with preset sizes for Instagram, YouTube, or custom dimensions.

Calculate exact age, next birthday countdown, and Chinese zodiac sign.

Pet Age Calculator

Estimate a cat or dog life stage and human-age equivalent using species and size-based rules.

Time Zone Converter

Convert between time zones globally with a built-in meeting planner.

TDEE Calorie Calculator

Calculate daily calorie needs with Mifflin-St Jeor formula. Includes weight goals.

AI Token Counter

Free token counter & API cost calculator for ChatGPT, Claude, Gemini. No login.

Format, minify, validate JSON instantly with error line numbers and dark mode.

Currency Converter

Real-time exchange rates for 30+ currencies including USD, EUR, JPY, GBP.

Base64 Encoder / Decoder

Convert text or images to and from Base64. Runs in your browser.

URL Encoder / Decoder

Encode or decode URLs containing spaces, special characters, or Unicode.

Unix Timestamp Converter

Convert between Unix timestamps and human-readable dates with multi-timezone support.

Generate UUID v4 identifiers in batches with one click.

Hash Generator (MD5/SHA)

Compute MD5, SHA-1, SHA-256, SHA-512 hashes for any text.

Strong Password Generator

Generate strong passwords with custom length, character types, and strength analysis.

Convert between HEX, RGB, HSL color formats with palette suggestions.

Percentage Calculator

Calculate X% of Y, percentage change, and other common percentage operations.

Countdown to Date

Live countdown timer to any future or past date.

Randomly pick from a list of options. Great for decisions.

Convert length, weight, temperature, volume, area, and speed across 40 units.

Decode JSON Web Tokens to view header, payload, and expiry status.

Test regular expressions with live highlighting and flag controls.

Markdown Editor

Live Markdown preview with HTML output for common syntax, tables, code, and task lists.

Compare two texts side-by-side. Highlight additions, deletions, changes.

Convert CSV to JSON and vice versa, with custom delimiters and header handling.

Convert text to UPPER, lower, Title, camelCase, PascalCase, snake_case, kebab-case.

Calculate BMI and health category from height and weight.

Roman Numeral Converter

Convert between Arabic numbers and Roman numerals (1 ↔ I, 4 ↔ IV).

Split restaurant bills evenly with optional tip calculation.

Focus timer using the 25/5 Pomodoro technique.

Lorem Ipsum Generator

Generate placeholder text in Latin or Chinese, by words/sentences/paragraphs.

Convert a basic YAML subset to JSON and back, including nested mappings, arrays, and scalars.

Fuel Cost Calculator

Calculate fuel costs from km/L efficiency, price, and distance. Includes EV mode.

Open Graph Preview

Preview how your website appears when shared on Facebook, Twitter, LINE.

Traditional Chinese AI Prompt Library

20+ Traditional Chinese prompts for ChatGPT, Claude, and Gemini, organized by category.

AI Prompt Optimizer

Auto-structure casual prompts with role, task, format. Boost AI response quality.

Animated GIF Maker

Combine multiple images into an animated GIF. Adjust frame delay and loop.

Combine multiple images into a single PDF with page settings.

Format, minify, and validate XML. Handles RSS, SOAP, SVG.

Background Remover

Two modes: AI human segmentation (MediaPipe) or solid-color chroma-key removal.

Weather Forecast

Live weather, 7-day forecast, and hourly temperature chart. Global cities. Data from Open-Meteo.

Scientific Calculator

Full scientific calculator with trig, log, exp, memory and history.

Convert iPhone HEIC photos to universal JPG or PNG in your browser.

Combine multiple PDFs into one. Drag to reorder. Browser-based, no upload.

Split a multi-page PDF into individual pages or custom ranges.

QR Code Scanner

Scan QR codes with your camera or upload an image to decode.

Live speech recognition with microphone. Supports English, Chinese, Japanese, Korean.

Search 1000+ curated emojis by name, browse by category, and copy with one click.

X & YouTube Character Limits

Check X weighted post length and YouTube title/description limits in real time.

US 4.0 scale GPA with credit weighting.

Final Grade Calculator

Calculate what you need on the final exam to reach a target grade.

Programmer Calculator (Hex/Bin/Oct)

Convert between DEC, HEX, BIN, OCT. Includes bitwise ops (AND/OR/XOR).

See your public IP, location, ISP, timezone. Look up any IP address.

Two modes: preserve-text (lossless cleanup) or rasterize-to-JPEG (maximum). Browser-based.

Convert each PDF page to PNG or JPG. Multi-page output as ZIP. Browser-based.

PDF Page Manager

Rotate, delete, and reorder PDF pages in your browser.

Add Page Numbers to PDF

Add page numbers to a PDF with custom position, size, and start number.

Add text watermarks such as CONFIDENTIAL, DRAFT, or a company name.

Draw a handwritten signature and place it onto a PDF page.

Image Format Converter

Convert JPG, PNG, WebP, AVIF, BMP, static GIF, and SVG to raster formats. Batch supported. Browser-based.

Auto-saves to your browser. No login. Markdown supported.

Random picker wheel. Great for classrooms, giveaways, decisions.

Crop images online with preset ratios and JPG/PNG/WebP output.

YouTube Thumbnail Viewer

Paste a YouTube URL to view available thumbnail sizes and open the original image.

Remove GPS, camera model, date, and other photo metadata.

Image Blur / Redact

Blur, pixelate, or black out sensitive information in screenshots and photos.

llms.txt Generator

Create an llms.txt file for AI search and answer engines.

AI Crawler Checker

Check whether robots.txt and llms.txt are friendly to AI search crawlers.

Schema Markup Generator

Generate WebSite, Organization, WebApplication, and Article JSON-LD.

FAQ Schema Generator

Convert questions and answers into FAQPage JSON-LD.

OCR (Image to Text)

Extract text from images. Chinese / English / Japanese / Korean. Browser-based.

CSS Gradient Generator

Live CSS gradient generator. Linear / radial / conic. Copy CSS instantly.

Favicon Generator

One image → all favicon sizes (16-512) + HTML tags. Browser-based.

JSON to TypeScript Interface

Paste JSON, get TypeScript interfaces / types with nested objects and array unions.

Color Palette Extractor

Extract dominant colors from any image. 5 / 8 / 12 color palettes.

Image Watermark

Add text or image watermarks to your photos. Browser-based.

Turn any title into a URL-friendly slug. SEO essential.

Decision Maker (Yes/No, Dice, Coin)

Can't decide? Let the tool decide. Yes/No, coin flip, dice roll, number picker.

Stopwatch / Timer

Online stopwatch with millisecond precision and lap recording.

Text-to-Speech (TTS)

Type text, hear it spoken. Multi-language, adjustable rate and pitch.

Gregorian ↔ Lunar Calendar

Convert Gregorian and Chinese lunar dates with sexagenary year and zodiac.

Chinese Zodiac & Western Zodiac

Enter your birthday to get your Chinese zodiac animal and Western zodiac sign.

PDF Password Protection

Add AES-128 password protection to a PDF in your browser. Decryption is not offered because rasterizing would damage the document.

CSV / Excel Online Preview

Open and view CSV, TSV, and Excel files in your browser. No Office needed.

Fake Chat Generator

Create iMessage / WhatsApp / LINE-style chat screenshots for memes and content.

Mars Text Generator

Transform text with Mars-style substitutions, bopomofo, upside-down, Zalgo, full-width, or mixed modes.

Word Unscrambler

Enter scrambled letters, get all valid English words. Scrabble & Words With Friends helper.

Enter a word or letters to find all anagrams (rearrangements that are valid words).

Crossword Solver

Enter a pattern like "C?T" or "_AT_" with missing letters to find matching words.

Find words that rhyme with any word. Great for songwriting, poetry, raps.

Random Word Generator

Generate random English words. Customize length, starting letter, count.

Loan Calculator

Compare equal-payment and equal-principal loans with fees, extra payments, payoff savings, and a complete amortization schedule.

Stock Average Calculator

Combine the average prices and current quantities shown by two or more brokers into one weighted stock average.

Compound Interest Calculator

Project future value from an initial balance, monthly deposits, rate, and compounding frequency.

Due Date Calculator

Estimate a due date by adding 280 days to the first day of the last menstrual period.

Placeholder Image Generator

Create a custom-size PNG placeholder with background, text, and text color.

Calorie Calculator

Estimate adult BMR with the Mifflin-St Jeor equation and apply a selected activity factor.

Age in Days Calculator

Count calendar days from a past date to today and convert them to hours and minutes.

Hourly to Salary Calculator

Convert hourly wage and weekly hours to gross monthly and annual pay using 52 weeks per year.

Salary to Hourly Calculator

Convert annual salary and weekly hours to an equivalent hourly wage and average monthly pay.

Upload an image and add fixed-style top and bottom meme text, then download a PNG.

Add Text to Image

Upload an image, add a centered bottom caption with a custom color, and download a PNG.

Number to Words

Convert a signed integer from zero through trillions into English words.

Aspect Ratio Calculator

Calculate one missing image dimension from a ratio and one known dimension.

Birthday Countdown

Count calendar days from today to the next occurrence of a birthday.

Time Card Calculator

Multiply hours per day by workdays and hourly wage to estimate total hours and gross pay.

Calculate a tip, bill total, and equal per-person split.

Discount Calculator

Calculate the sale price and savings for one 0-100% discount.

Speed Distance Time Calculator

Enter exactly two positive values to calculate speed, distance, or time.

Cooking Conversion Calculator

Free online cooking conversion calculator for quick everyday calculations and image tasks.

Date Calculator

Add or subtract days from any date and get the exact result date.

Date Difference Calculator

Calculate the number of days and weeks between two dates.

Business Days Calculator

Count weekdays between two dates, excluding Saturday and Sunday.

Hours Calculator

Calculate work hours between two times with optional break minutes.

Time Duration Calculator

Find the total hours and days between two date/time values.

Estimate basal metabolic rate using height, weight, age, and gender.

Macro Calculator

Split daily calories into protein, carbs, and fat targets.

Body Fat Calculator

Estimate body fat percentage with the US Navy tape method.

Ovulation Calculator

Estimate ovulation day and fertile window from your cycle.

Period Calculator

Estimate your next period start and expected period range.

Concrete Calculator

Estimate concrete volume; bag count explicitly assumes 0.017 m³ yield per 40kg bag.

Paint Calculator

Estimate how much paint you need for a rectangular room.

Format compact HTML into readable indented markup.

Format SQL queries with line breaks and uppercase keywords.

PII Masking Tool

Mask names, phone numbers, IDs, emails, and addresses before sharing text.