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Calculators, converters, developer tools, and AI-powered utilities — all free, no signup required. Powered by public APIs and browser-based AI.
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BMI Calculator
Work out your BMI, and the measurement current NICE guidance asks for alongside it: waist-to-height ...
Age Calculator
Your exact age in years, months and days plus every other unit, the weekday you were born, your next...
Percentage Calculator
Eight percentage calculations with the working shown: percent of a number, percent change, percent d...
Tip Calculator
Work out the tip on the pre-tax or post-tax amount and see what the choice costs, split the bill any...
Unit Converter
Convert across 12 categories and 90+ units, and see the conversion factor used — including whether i...
Mortgage Calculator
Full PITI payment with taxes, insurance, HOA and PMI — plus the exact month your PMI ends under fede...
Currency Converter
Convert 166 currencies at the mid-market rate, then see what a card, bank or bureau would actually g...
Compound Interest Calculator
Compound interest with contributions on their own schedule, the effective annual rate, an inflation-...
JSON Formatter & Validator
Format and validate JSON in your browser, nothing uploaded. Covers the six value types, why trailing...
Base64 Encoder & Decoder
Encode text to Base64 or decode Base64 back to text. Free online Base64 tool for developers. No sign...
URL Encoder & Decoder
Encode and decode URLs in your browser, with a full percent-encoding reference and the encodeURI vs ...
Regex Tester
Test regular expressions live against the JavaScript engine, with a flavour comparison for Python, J...
All Tools
Browse all 165+ free online tools
BMI Calculator
Work out your BMI, and the measurement current NICE guidance asks for alongside ...
Age Calculator
Your exact age in years, months and days plus every other unit, the weekday you ...
Percentage Calculator
Eight percentage calculations with the working shown: percent of a number, perce...
Tip Calculator
Work out the tip on the pre-tax or post-tax amount and see what the choice costs...
Unit Converter
Convert across 12 categories and 90+ units, and see the conversion factor used —...
Mortgage Calculator
Full PITI payment with taxes, insurance, HOA and PMI — plus the exact month your...
Currency Converter
Convert 166 currencies at the mid-market rate, then see what a card, bank or bur...
Compound Interest Calculator
Compound interest with contributions on their own schedule, the effective annual...
JSON Formatter & Validator
Format and validate JSON in your browser, nothing uploaded. Covers the six value...
Base64 Encoder & Decoder
Encode text to Base64 or decode Base64 back to text. Free online Base64 tool for...
URL Encoder & Decoder
Encode and decode URLs in your browser, with a full percent-encoding reference a...
Regex Tester
Test regular expressions live against the JavaScript engine, with a flavour comp...
Word Counter
Count words, characters, sentences, and paragraphs in your text. Estimate readin...
Case Converter
Convert text to every case at once — sentence, title (both AP and Chicago rules)...
Lorem Ipsum Generator
Generate placeholder text from the real 186-word Cicero vocabulary, as paragraph...
Character Counter
Counts what you actually see, not UTF-16 units — so an emoji counts as one, not ...
Sunrise & Sunset Calculator
Find sunrise and sunset times for any location and date. Calculate day length an...
QR Code Generator
Generates QR codes entirely in your browser — nothing is uploaded. Static and pe...
Color Palette Generator
Seven harmonies built in HSL, with the contrast ratio and pass/fail on each colo...
Password Generator
Generate strong, secure passwords with customizable length and character types. ...
Readability Score Checker
Check the readability of your text with Flesch-Kincaid, Gunning Fog, and Coleman...
AI Sentiment Analyzer
Score text from −100 to +100 sentence by sentence, so a mixed review reads as mi...
Loan Payoff Calculator
See how extra payments cut your loan short. Get payoff date, total interest save...
Salary & Tax Calculator
Estimate take-home pay using 2026 IRS brackets and the $184,500 Social Security ...
Profit Margin Calculator
Gross margin, markup, net profit and breakeven from cost and price — plus the pr...
TDEE & Calorie Calculator
Calculate your Total Daily Energy Expenditure (TDEE), BMR, and daily calorie tar...
Diff Checker & Text Compare
Compare two texts side by side in your browser, nothing uploaded. Explains unifi...
Auto Loan Calculator
Estimate your car payment with tax and trade-in, then see how long each term lea...
Retirement & 401(k) Calculator
Project your nest egg and safe withdrawal with the 4% rule, plus what a single-a...
Invoice Generator
Create professional invoices instantly online with taxes, custom currencies, and...
Discount Calculator
Sale price, stacked "extra % off" discounts that compound rather than add, sales...
CSV to JSON Converter
Convert CSV to JSON in your browser, with control over type inference so leading...
Markdown Live Previewer
Write and preview GitHub-flavored markdown in real time. Features instant split-...
Daily Water Intake Calculator
How much water to drink daily by weight, exercise and climate — and the part oth...
College & High School GPA Calculator
Semester, cumulative and weighted GPA in one place — with AP and honors bumps, p...
UTM Campaign URL Builder
Build custom campaign tracking URLs with standard UTM parameters for Google Anal...
Macro & Calorie Deficit Calculator
Daily protein, carb and fat targets from the Mifflin-St Jeor equation — and the ...
Aspect Ratio Calculator
Calculate aspect ratios and scale image and video dimensions proportionally with...
HEX to RGB Color Converter
Convert HEX color codes to RGB, RGBA, HSL, and CMYK formats instantly. Includes ...
HTML to Markdown Converter
Convert HTML code snippets, articles, and rich text to clean GitHub-flavored mar...
Credit Card Payoff Calculator
Calculate how long to pay off your credit card balance, total interest costs, mi...
Simple Interest Calculator
Simple interest on any principal, rate and term, with the 365 and 360-day conven...
Inflation & Purchasing Power Calculator
Convert money between any two years using the official BLS CPI-U series, the sam...
Net Worth Calculator
Calculate your total personal net worth by balancing assets (cash, investments, ...
Hourly to Salary Converter
Convert an hourly rate to annual pay, showing both figures side by side. Unpaid ...
Down Payment Savings Calculator
See the cash you need at 3%, 3.5% FHA, 10% or 20% down, whether PMI applies, and...
Future Value (FV) Calculator
Calculate the future value of a lump-sum investment and recurring monthly cash f...
Capital Gains Tax Calculator
Estimate capital gains tax with 2026 IRS brackets. Handles gains that straddle t...
US Navy Body Fat Calculator
Estimate body fat from a tape measure with the US Navy formula, cross-checked ag...
Ideal Body Weight (IBW) Calculator
Compare all four IBW formulas plus adjusted body weight — and see why they disag...
Target Heart Rate Calculator
Get your five training zones from a max heart rate formula that is actually vali...
Sleep Cycle & Bedtime Calculator
Work out your bedtime or wake-up time from real 90–110 minute sleep cycles, with...
Lean Body Mass (LBM) Calculator
Lean body mass and FFMI from three published equations — with the James formula ...
Calorie Burned Activity Calculator
Calories burned for 30+ activities using standard MET values — and the number no...
Pregnancy Due Date Calculator
Calculate your estimated baby due date, current gestational age in weeks and day...
Blood Pressure Category Checker
Check a reading against the ACC/AHA categories — and why "normal blood pressure ...
Running Pace & Split Calculator
Pace per km and mile, treadmill speed, and race predictions that use Riegel's fo...
Cryptographic Hash Generator
Generate secure cryptographic checksums and hashes (SHA-256, SHA-512, SHA-384, S...
JWT Token Decoder & Inspector
Decode and inspect JSON Web Tokens (JWT) safely client-side. View decoded header...
Cron Expression Generator
Build cron expressions with plain-English output, common recipes, and the field-...
SQL Formatter & Beautifier
Format SQL for readable diffs and code review, with an identifier-quoting table ...
UUID / GUID v4 Generator
Generate bulk cryptographically secure Version 4 UUIDs (Universally Unique Ident...
Unix Epoch Timestamp Converter
Convert Unix epoch timestamps (seconds & milliseconds) to human-readable UTC and...
HTML Entity Encoder / Decoder
Encode and decode HTML entities with a full reference table, plus why entity enc...
CSS Box Shadow Generator
Create beautiful CSS box shadows, 3D elevations, and inset effects with interact...
CSS Gradient Generator
Create vibrant CSS linear and radial gradients with custom color stops, angles, ...
Breakeven Point Calculator
Find break-even in units and revenue from fixed costs and contribution margin, p...
Return on Investment (ROI) Calculator
Calculate return on investment and the annualized rate that makes different hold...
PayPal Fee Calculator
Calculate PayPal merchant transaction deductions (2.99% + $0.49), international ...
Stripe Fee Calculator
Calculate Stripe credit card processing deductions (2.9% + 30¢), international c...
Markup Calculator
Calculate retail selling price, dollar profit, and understand the difference bet...
CPM (Cost Per Mille) Calculator
Calculate Cost Per Thousand Impressions (CPM), required advertising budget, or t...
A/B Test Significance Calculator
Check if your A/B test is statistically significant. Get p-value, Z-score, confi...
CTR (Click-Through Rate) Calculator
Calculate digital ad and organic search Click-Through Rate (CTR %), conversion r...
Freelance Hourly Rate Calculator
Calculate your ideal freelance hourly bill rate and day rate based on desired ta...
Pomodoro Timer
A 25/5 Pomodoro timer with custom intervals, automatic long breaks and an alarm ...
Stopwatch & Countdown Timer
Stopwatch with laps and a countdown timer, both driven by the system clock so th...
Words to Pages Calculator
Convert word count to exact document page count. Customize single/double spacing...
SEO URL Slug Generator
Turn any title into a clean lowercase URL slug. Covers accent stripping limits, ...
Duplicate Line Remover
Remove duplicate lines from text, email lists, and code instantly. Options for c...
Keyword Density & Frequency Checker
Analyze keyword frequency and n-gram density percentage (1-word, 2-word, 3-word ...
Test Grade Percentage Calculator
Calculate test score percentages, letter grades (A+ to F), and GPA equivalents b...
Final Grade Calculator
Calculate the exact minimum score you need on your final exam to pass your class...
Roman Numeral Converter
Convert numbers and dates to Roman numerals and back — and unlike most converter...
Moon Phase & Lunar Calendar Tracker
Track the current moon phase, illumination percentage, lunar age, and exact coun...
World Clock & Global Timezone Converter
View real-time accurate local time and date comparisons across 12 major global f...
Heat Index & Real-Feel Calculator
Calculate the NOAA Heat Index ("feels like" temperature) from air temperature an...
Wind Chill Index & Frostbite Risk Calculator
Calculate the National Weather Service (NWS) Wind Chill temperature and estimate...
Dew Point & Humidity Comfort Calculator
Calculate atmospheric dew point temperature and human comfort levels using the M...
HTTP Status Code Explainer
Search all standard HTTP response status codes (200, 301, 404, 500, 502, 503) wi...
User Agent & Browser Inspector
Instantly parse and analyze your browser user-agent string, operating system ver...
IP Subnet Mask & CIDR Calculator
Calculate IPv4 subnet masks, CIDR network prefixes (/24, /16), network IDs, broa...
TCP / UDP Port Database Reference
Search common TCP/UDP network ports (22, 80, 443, 3306, 5432, 8080) with protoco...
JSON to XML & XML to JSON Converter
Convert JSON payloads into clean, indented XML structures and vice-versa. Custom...
JSON to YAML & YAML to JSON Converter
Convert JSON to YAML and back in your browser. Covers implicit typing: why versi...
HTML, CSS & JSON Code Minifier & Formatter
Minify and beautify HTML, CSS, and JSON code client-side. Reduce file payload si...
Interactive Regex Builder & Tester
Test and debug regular expressions in real-time with group capture inspection, f...
Linux Chmod Permissions Calculator
Calculate Linux/Unix file permissions with interactive read, write, and execute ...
Markdown Table Generator & Spreadsheet
Create and format Markdown tables using a visual spreadsheet editor. Add rows, c...
WCAG 2.2 Color Contrast Ratio Calculator
Check color contrast ratios between text and background colors. Instant WCAG 2.2...
RFC 4648 Base32 Encoder & Decoder
Encode text to Base32 or decode Base32 strings into plain text using standard RF...
JWT (JSON Web Token) Builder & Simulator
Build custom JWT tokens with customizable header claims, payload claims, and HMA...
SEO Robots.txt & Sitemap Directives Generator
Build a valid robots.txt with correct Allow/Disallow precedence, and understand ...
Rule of 72 Compound Interest Calculator
Calculate how many years it will take to double your investment money at any ann...
Rent vs Buy Real Estate Calculator
Find the year buying beats renting, counting selling costs and the investment re...
Emergency Fund & Safety Net Calculator
Work out your target from essential expenses, pick 3, 6, 9 or 12 months based on...
Auto Lease vs Buy & Cost of Ownership Calculator
Compare the true financial cost of auto leasing vs loan financing. Accounts for ...
Stock Dividend Yield & DRIP Calculator
Calculate stock dividend yield percentages, annual cash flow income, and project...
Stock Options Profit & Breakeven Simulator
Calculate net profit, loss, breakeven stock prices, and return on capital for Lo...
Home Equity & HELOC Borrowing Calculator
See how much you can borrow against your home and the exact monthly payment. Inc...
Loan & Mortgage Amortization Schedule
Generate the complete payment-by-payment amortization schedule. Download as CSV ...
Net Effective Rent & Concession Calculator
Calculate the true net effective monthly rent on apartment leases factoring in p...
Commercial Real Estate Cap Rate Calculator
Calculate commercial real estate Capitalization Rate (Cap Rate), Net Operating I...
SaaS Subscription MRR & ARR Calculator
Calculate software-as-a-service Monthly Recurring Revenue (MRR), Annual Recurrin...
Standard Deviation & Variance Calculator
Sample and population standard deviation with the full working shown, plus relat...
Standard Normal Z-Score & Percentile Calculator
Z-score to percentile and back, with the step most calculators skip: for a sampl...
Interactive Periodic Table of Elements
Interactive periodic table of chemical elements. Search by element name, symbol,...
Scientific & Engineering Notation Converter
Convert between decimal, scientific, E-notation and engineering notation without...
Quadratic Equation Formula Solver
Solve quadratic equations (ax² + bx + c = 0) with step-by-step discriminant (Δ =...
Right Triangle Trigonometry & Pythagorean Calculator
Solve a right triangle from any two values — two legs, a leg and the hypotenuse,...
Circle Area, Circumference & Diameter Calculator
Solve a circle from radius, diameter, circumference or area — plus arc length, s...
Fraction Arithmetic & Simplifier Calculator
Add, subtract, multiply and divide fractions — including mixed numbers and a thi...
Significant Figures Counter & Rounding Calculator
Count significant figures and round correctly — including the ambiguous cases li...
Ohms Law & Electrical Power Calculator
Enter any two of voltage, current, resistance or power and get the other two — p...
4-Band Resistor Color Code Decoder
Decode 4-band resistor colours to ohms, and look the other way too — the colour ...
Matrix Determinant Calculator (2×2 to 5×5)
Determinants for 2×2, 3×3, 4×4 and 5×5 matrices with the cofactor expansion show...
Binary, Decimal & Hex Converter
Convert between binary, octal, decimal and hex with arbitrary precision, so 64-b...
Logarithm & Natural Log (ln) Calculator
Solve for any part of log₆(x) = y — the logarithm, the antilog or the base — wit...
Prime Number Tester & Factorization Generator
Prime factors, divisor count and primality — plus the square root in simplest ra...
Permutations (nPr) & Combinations (nCr) Calculator
nPr and nCr with and without repetition — all four cases, in exact arbitrary pre...
Morse Code Translator
Translate text and Morse in both directions using the complete ITU alphabet, wit...
English Text to Grade 1 Braille Translator
Convert English letters, numbers, and punctuation marks into standard Grade 1 Un...
pH Scale & Hydrogen Ion [H+] Concentration Calculator
pH from concentration, molarity or Ka — with the temperature caveat every other ...
Recipe Portion & Serving Size Scaler
Scale recipe ingredient quantities up or down automatically by serving size or p...
Specialty Coffee Brew Ratio Calculator
Calculate golden coffee-to-water brewing ratios (1:15 to 1:18) for Pour Over (V6...
Boiled Egg Cooking Timer (Soft, Jammy & Hard)
Exact boiling times for soft, jammy and hard-boiled eggs. Adjusts for egg size, ...
Musical Note Pitch to Audio Frequency (Hz) Finder
Convert musical note pitch and octave numbers to equal temperament frequency in ...
Music BPM to Delay Milliseconds & LFO Rate Calculator
Calculate audio delay time in milliseconds (ms), reverb pre-delay, and LFO frequ...
Camera Sensor Crop Factor & Focal Length Equivalent
Calculate 35mm full-frame equivalent focal length (mm), field of view classifica...
Photography Exposure Value (EV) & Lux Calculator
Calculate photography Exposure Value (EV100), ambient scene illuminance in Lux, ...
Speech Duration & Reading Time by WPM Pace Calculator
Estimate spoken presentation duration and silent reading time based on word coun...
Golden Hour & Blue Hour Photography Lighting Calculator
Calculate morning and evening Golden Hour and Blue Hour natural light windows fr...
Image Compressor
Compress JPG, PNG and WebP to an exact file size, or by quality. Runs in your br...
Image Resizer
Resize an image by pixels, percentage, inches or millimetres at a chosen DPI. Pr...
Image Converter
Convert between JPG, PNG and WebP with control over the background colour behind...
PNG to JPG Converter
Convert PNG to JPG in your browser, choosing the colour that replaces transparen...
JPG to PNG Converter
Convert JPG to PNG without uploading anything. Honest about what it does and doe...
Merge PDF
Combine PDFs into one file without uploading them anywhere. Set the order, see p...
Split PDF
Extract a page range, delete pages, or split a PDF into separate files. Multiple...
JPG to PDF Converter
Turn JPG, PNG and WebP images into a single PDF. Page size matched to each image...
PDF to JPG Converter
Turn PDF pages into JPG, PNG or WebP at a resolution you choose, with the output...
Rotate PDF
Turn PDF pages 90, 180 or 270 degrees and save the rotation into the file. Adds ...
Signature & Photo Resizer
Fit a signature or photo to exact pixel dimensions AND a KB range, not just a ce...
Image Cropper
Crop to a locked aspect ratio and set the exact output pixels — in px, inches, c...
Background Remover
Remove the background from a portrait in your browser. Full resolution, no credi...
Compress PDF
Shrink a PDF to an exact target size, and be told first whether it is a scan (sa...
Watermark PDF
Stamp text across every page or a selection: diagonal or straight, any size, opa...
Add Page Numbers to PDF
Number a PDF with the position and format you want, skipping a cover and startin...
Image to Text (OCR)
Extract text from an image in your browser, with a per-word confidence score so ...
PDF to Text
Pull the real text out of a PDF with paragraphs rebuilt from the document’s own ...
Favicon Generator
Make a favicon from an image, letters or an emoji. A genuine multi-image .ico, t...
SVG to PNG
Rasterise an SVG at any scale with no loss. Checks first for external fonts, rem...
Image Color Picker
Pick colours from a photo as HEX, RGB and HSL. Samples an area rather than one n...
Passport Photo Maker
Crop to 35×45 mm, 2×2 in or any size at a chosen DPI, with head-height guides, t...
QR Code Scanner
Scan a QR code from your camera or an image and see exactly what it contains. No...