Simple Interest Calculator
Work out simple interest on any principal, rate and duration, in twenty currencies. Shows the interest, the total amount and how the figure was reached. Runs entirely in your browser.
Utilities
Free Online Tools
Fast, private and free, with no signup. 94 tools across 7 categories, and every one of them runs inside your browser - nothing you enter is uploaded, stored or logged.
Runs locally in your browser Your input is not uploaded or stored by our server.
26 available
Calculators
Tax, employment, savings and interest, using the rules that apply where you are.
Compound Interest Calculator
Calculate compound growth with any compounding frequency and optional regular contributions. Shows the year-by-year breakdown, total invested and interest earned. Runs entirely in your browser.
Loan EMI Calculator
Work out the monthly payment on a home, car or personal loan, and see how much of each year goes on interest rather than the balance. Runs entirely in your browser.
SIP Calculator
Project what a monthly investment plan could grow to, with an optional annual step-up and a one-off amount. Shows what you put in against what the returns added. Runs in your browser.
CAGR Calculator
Work out the compound annual growth rate between any two values over any period. Shows the growth multiple, the total return and how long a doubling would take. Runs in your browser.
FD Calculator
Work out what a fixed deposit matures to, at any rate, term and compounding basis. Shows the effective annual yield and the difference between a cumulative and a payout deposit. Runs in your browser.
RD Calculator
Work out what a recurring deposit matures to, using the quarterly compounding banks actually apply. Shows the interest, the instalment count and a year-by-year breakdown. Runs in your browser.
Age Calculator
Work out an exact age in years, months and days, with total weeks and days, the weekday you were born on and the time to your next birthday.
Percentage Calculator
Work out a percentage of a number, what one number is as a percentage of another, and percentage increase or decrease - with the working shown.
27 available
Developer Tools
Format, validate, inspect and convert the formats you work in every day.
JSON Formatter & Validator
Free online JSON formatter, validator and beautifier. Format, validate, minify and inspect JSON directly in your browser. Your JSON never leaves your device.
JSON Validator
Free online JSON validator. Check JSON syntax and get the exact line, column and cause of every error, then repair common mistakes in one click.
Base64 Encoder & Decoder
Encode text to Base64 and decode it back, in your browser. Handles accents, emoji and any other Unicode correctly, with URL-safe and MIME line-wrapped output.
JWT Decoder
Decode the header and payload of a JSON Web Token in your browser. Your token is never uploaded, which matters more here than for any other tool on this site.
UUID Generator
Generate version 4 UUIDs in bulk using your browser's cryptographic random number generator. Uppercase, hyphen-free and brace-wrapped formats included.
Regex Tester
Test a regular expression against your own text and see every match, its position and its capture groups highlighted in place. Runs in your browser.
17 available
Converters
Length, weight, temperature, area and data size, converted instantly.
Length Converter
Convert between millimetres, centimetres, metres, kilometres, inches, feet, yards, miles and nautical miles. Instant, exact and entirely in your browser.
Weight Converter
Convert between milligrams, grams, kilograms, tonnes, ounces, pounds, stone and US tons. Runs entirely in your browser.
8 available
Text Tools
Count, transform, sort, deduplicate and compare text.
Word Counter
Count words, characters, sentences and paragraphs as you type, with reading and speaking time. Nothing you write is uploaded.
Character Counter
Count characters with and without spaces, live, against the limits that platforms impose. Runs entirely in your browser.
9 available
QR Tools
QR codes for links, Wi-Fi, contacts and messages, generated on your device.
QR Code Generator
Turn a link or any text into a QR code and download it as SVG or PNG. Generated in your browser, with no account, no tracking and no expiry.
Wi-Fi QR Code
Make a QR code guests can scan to join your Wi-Fi without typing the password. The password is encoded on your device and never sent anywhere.
4 available
Web & Design
Colours, gradients and contrast checks for building interfaces.
Color Picker
Pick a colour and read it back as HEX, RGB, HSL and HSV, with its complement and a tint and shade ramp. Runs entirely in your browser.
Contrast Checker
Check a text and background colour against WCAG 2.2 AA and AAA, for normal text, large text and interface components.
3 available
Image Tools
Resize, compress and convert images without uploading them anywhere.
Image Resizer
Resize an image to exact dimensions or a preset, keeping the aspect ratio. Everything happens in your browser - the file is never uploaded.
Image Compressor
Reduce an image's file size with a quality setting and an optional maximum width. Shows the before and after, and never uploads the file.
How this works
Your Data Stays in Your Browser
Every tool here is built the same way: your input is read by the page, processed by JavaScript on your own device, and shown back to you. It is never sent to a server, which is why there is nothing to sign up for and nothing for us to store.
Questions
Frequently Asked Questions
- Do I need an account?
- No. There is nothing to sign up for and nothing to log in to. Open a tool, use it, copy or download the result and leave.
- Is anything I enter uploaded?
- No. Every tool listed here runs entirely inside your browser using JavaScript. Nothing you paste, type or open is sent to our servers, stored or logged. You can disconnect from the network after a tool's page has loaded and it keeps working.
- Are the tools free?
- Yes, all of them, with no usage limits and no paid tier.
- What is the difference between the calculators and the developer tools?
- The calculators work out financial figures - tax, interest, loans, employment benefits - using the rules of the country you pick. The developer tools work on data formats such as JSON, YAML, XML and CSV. Both run locally and neither needs an account.