Free Online Calculators, Converters & Tools
68 free tools for finance, development, and everyday tasks. No account required, instant results in your browser.
Popular tools
Loan Repayment Calculator
A free loan repayment calculator for monthly payments, total interest, and the full cost of borrowing on any fixed-rate loan — mortgage, car, student or personal.
Currency Converter
Convert between 30 world currencies with live or manual exchange rates. Handles USD, EUR, GBP, JPY, CNY, and more.
JSON Formatter & Validator
Format, validate, and minify JSON with syntax highlighting and error detection. Runs entirely in your browser.
Password Generator
Generate strong random passwords with custom length, uppercase, lowercase, numbers, and symbols.
Unit Converter
Convert between units of length, weight, temperature, area, and speed. Results update instantly.
Percentage Calculator
Calculate percentage of a number, what percentage one value is of another, and percentage change — three calculators in one.
Finance & Math
Loan Repayment Calculator
A free loan repayment calculator for monthly payments, total interest, and the full cost of borrowing on any fixed-rate loan — mortgage, car, student or personal.
Mortgage Calculator
Use this free mortgage calculator to estimate your monthly payment with principal, interest, property tax, home insurance, PMI and HOA — plus total interest and how extra payments shorten the loan.
Auto Loan Calculator
Estimate a car loan's monthly payment from vehicle price, down payment, trade-in, sales tax, APR and term — with total interest and the true cost of the car.
Loan Affordability Calculator
Find the maximum loan amount you can afford based on your monthly budget and interest rate.
Salary Calculator
Convert a wage between hourly, daily, weekly, biweekly, monthly and annual pay. Adjust hours per week and unpaid time off to see every gross equivalent.
Sales Tax Calculator
Add sales tax to a price or work backwards from a tax-included total. Load a US state base rate or enter your own combined rate.
Currency Converter
Convert between 30 world currencies with live or manual exchange rates. Handles USD, EUR, GBP, JPY, CNY, and more.
Percentage Calculator
Calculate percentage of a number, what percentage one value is of another, and percentage change — three calculators in one.
Discount Calculator
Calculate final price after a discount, the savings amount, or reverse-engineer the discount rate from two prices.
Tip Calculator & Bill Splitter
Calculate the tip amount and split the total bill equally between any number of people.
Compound Interest Calculator
See how investments grow over time with compound interest, including regular monthly contributions.
ROI Calculator
Calculate return on investment as a percentage, net profit, and the annualized rate (CAGR) over the holding period.
Date & Time
Date Difference Calculator
Calculate the exact number of days, weeks, and months between any two dates. Handles leap years automatically.
Date Calculator — Add or Subtract Days
Add or subtract years, months, weeks and days from any date to get the resulting date and weekday. Answers "what date is 90 days from today?"
Age Calculator
Calculate exact age in years, months, and days from a date of birth. Shows total days lived and days until next birthday.
Time Zone Converter
Convert any date and time between 18 world time zones. Daylight saving time is handled automatically.
Unix Timestamp Converter
Convert a Unix timestamp (seconds or milliseconds) to a readable date in UTC, ISO 8601 and local time — and convert any date back to a timestamp. Live current epoch time.
Business Days Calculator
Count the working days between two dates, excluding weekends and, optionally, the eleven US federal holidays, with a full day breakdown.
Developer Tools
JSON Formatter & Validator
Format, validate, and minify JSON with syntax highlighting and error detection. Runs entirely in your browser.
JSON to CSV Converter
Convert a JSON array of objects to CSV with a choice of delimiter and an optional header row. Handles missing keys and nested values.
CSV to JSON Converter
Convert CSV to a JSON array of objects or arrays, with delimiter choice, header handling and optional number/boolean type inference. RFC 4180 quoting respected.
YAML to JSON Converter
Convert YAML to JSON in your browser, with a choice of indent or minified output and clear parse-error messages. Anchors and aliases are expanded.
JSON to YAML Converter
Convert JSON to block-style YAML in your browser, with a choice of indent and optional key sorting. Strings are quoted only when ambiguous.
CSS Formatter & Minifier
Beautify CSS with one rule per line and indented at-rules, or minify it by stripping comments and whitespace. String- and url()-safe.
HTML Formatter & Minifier
Beautify HTML by re-indenting to nesting depth (inline content stays on one line, pre/script/style preserved), or minify it by collapsing whitespace between tags.
Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 strings back to plain text. Supports Unicode, emoji, and non-Latin characters.
Hash Generator (SHA-1, SHA-256, SHA-384, SHA-512)
Generate SHA-1, SHA-256, SHA-384 and SHA-512 hashes of text or a file, entirely in your browser with the Web Crypto API. Nothing is uploaded.
JWT Decoder
Decode a JSON Web Token to read its header and payload, with exp, iat and nbf shown as readable dates and an expiry check. In-browser; the signature is not verified.
Number Base Converter
Convert an integer between binary, octal, decimal, hexadecimal and any base from 2 to 36, live. Arbitrary-size integers supported.
Color Converter — HEX, RGB, HSL
Convert colors between HEX, RGB, HSL, and HSB/HSV formats instantly. Includes a visual color picker.
URL Encoder / Decoder
Encode special characters in URLs using percent-encoding, or decode percent-encoded URLs back to readable text.
URL Shortener
Turn long URLs into short, shareable links via TinyURL, is.gd, or cleanuri — with a one-tap copy button, QR code, and local history. No sign-up required.
Regex Tester
Test regular expressions with live match highlighting. Supports flags (g, i, m) and shows capture groups.
HTML Encoder / Decoder
Convert special characters to HTML entities and decode HTML entities back to plain text.
Cron Expression Generator
Build and validate cron expressions visually with a plain-English schedule description. Copy-paste ready output.
Lorem Ipsum Generator
Generate placeholder Lorem Ipsum text by paragraphs, sentences or words, with an optional classic opening line and <p> tag wrapping.
SEO Tools
Meta Tag Generator
Build a copy-paste <head> block — title, description, canonical, robots, Open Graph and Twitter Card tags — with a live Google result preview and character counters.
Slug Generator
Turn any title into a clean, URL-safe slug: lowercased, accent-stripped, punctuation removed, words joined with a hyphen or underscore. One title per line.
robots.txt Generator
Build a valid robots.txt from per-user-agent Allow/Disallow rules, a sitemap line and an optional crawl-delay, with presets including blocking AI crawlers.
Keyword Density Checker
Paste text to see word and phrase frequency and density for one-, two- and three-word phrases, with stop-word filtering. Spot missing topics and keyword stuffing.
Text Tools
Word Counter & Character Count
Count words, characters, sentences, and paragraphs instantly. Includes reading time estimates.
Character Counter
Count characters with and without spaces, plus words, lines and sentences, with live progress against meta title, meta description, SMS and tweet limits.
Case Converter
Convert text between UPPERCASE, lowercase, Title Case, camelCase, PascalCase, snake_case, and kebab-case.
Find and Replace Text
Find and replace across a block of text — plain or regular-expression search, case-insensitive matching, and $1 group references in regex mode. Shows the match count.
Sort Text Lines
Sort lines alphabetically, numerically, by length, in reverse or shuffled, with options to trim, drop blanks, remove duplicates and ignore case.
Remove Duplicate Lines
Strip repeated lines from a list, keeping the first or last occurrence, with trim, case-fold, blank-line and sort options. Shows how many lines were removed.
Diff Checker
Compare two blocks of text and see a line-by-line diff with added and removed lines highlighted, plus options to ignore whitespace and case.
Markdown Editor & Preview
Write Markdown with a live side-by-side HTML preview. Supports full CommonMark syntax. Runs in your browser.
Image Tools
Image Compressor
Compress JPEG, PNG or WebP in your browser. Cap the long edge, set quality, compare file sizes and download. Nothing is uploaded.
Image Resizer
Resize an image by pixels or percent, keep the aspect ratio, and export JPEG, PNG or WebP. Runs entirely in your browser.
Image Converter — PNG, JPEG, WebP
Convert images between PNG, JPEG and WebP in your browser. Preview the result and download. Nothing is uploaded.
Image Cropper
Crop photos in the browser with free or locked ratios (1:1, 4:3, 16:9, 9:16). Drag to reframe and download. Nothing is uploaded.
Image Rounded Corners
Round image corners in your browser: drag the slider to set the rounded corner radius, preview it on a checkerboard, keep the corners transparent as PNG or WebP, and download. Nothing is uploaded.
Image to Base64 Converter
Turn an image into a Base64 data URI (or raw Base64), or paste Base64 back into a PNG. Encoding stays in your browser.
Favicon Generator
A free favicon generator that converts PNG, JPG, WebP or SVG — or a few letters or an emoji — to a multi-size favicon.ico (16, 32 and 48 px), a dark-mode-aware favicon.svg, Apple touch icon, Android Chrome 192/512, HTML tags and a web manifest. Runs in your browser.
App Icon Generator
Generate iOS and Android app icons from one image: AppIcon sizes including 1024×1024, mipmap densities, and a 512 Play Store asset. Nothing is uploaded.
Chrome Extension Icon Generator
Create Chrome extension icons at 16, 32, 48 and 128 from one image. Download a ZIP with an icons/ folder and a manifest.json snippet. Nothing is uploaded.
ID Photo Maker & Background Remover
A free ID photo maker that runs in your browser: remove background from a photo with on-device AI and turn it into a standard ID or passport photo — pick the size and background color, plus an optional 6-inch print sheet. Nothing is uploaded.
Utilities
Password Generator
Generate strong random passwords with custom length, uppercase, lowercase, numbers, and symbols.
Random Number Generator
Generate random integers or decimals within any range. Supports multiple numbers and no-duplicate mode.
BMI Calculator
Calculate your Body Mass Index (BMI) from height and weight in metric or imperial units.
TDEE & Calorie Calculator
Calculate your Total Daily Energy Expenditure and daily calorie targets for weight loss, maintenance, or gain.
Calorie Calculator
Find how many calories to eat per day to lose, maintain or gain weight, based on your BMR, activity level and goal (Mifflin-St Jeor equation).
Macro Calculator
Split a daily calorie target into grams of protein, carbs and fat using a preset or custom ratio, based on the 4/4/9 kcal-per-gram Atwater factors.
Body Fat Calculator
Estimate body fat percentage from tape measurements using the US Navy method, with body-fat category, fat mass and lean body mass.
Unit Converter
Convert between units of length, weight, temperature, area, and speed. Results update instantly.
UUID Generator
Generate RFC 4122 UUIDs in v1, v4, or v5 format. Options for quantity, uppercase, and hyphen formatting.
QR Code Generator
Create a QR code from text, a URL, or Wi-Fi login details in your browser. Download PNG or SVG. Nothing is uploaded.
What is PlayTools, and who is it for?
PlayTools is a free collection of calculators, converters, and lightweight utilities that run in your web browser. Whether you are comparing loan options, checking your BMI, formatting JSON for an API, or generating a UUID for a database key, you can get an answer in seconds — no account, no install. It is built for students, independent developers, small-business owners, and anyone who needs fast, dependable numbers or text transformations during a busy day.
The finance tools cover loan repayment and affordability, compound interest, tips, discounts, and currency conversion with live or manual rates. Date and time helpers handle age, time-zone conversion, and the number of days between two dates. For developers there is JSON formatting and validation, Base64 and URL encoding, cron-expression building, regex testing, and HTML encoding. Most tools run on your device, so the figures and text you type are not sent to a server just to get a result.
When a tool relies on a published formula or standard band — such as BMI categories or fixed-rate loan amortization — the assumptions are explained on that tool’s page so you can read the result in context. For legal, medical, or major financial decisions, please confirm with a qualified professional: these tools are educational and convenience aids, not a substitute for personalised advice.
Browse every tool in the categories above, or open the full tools directory to search the complete list in one place. Everything stays free, so bookmark the pages you reach for most and come back whenever you need a quick check.