Tools
Age Calculator
Calculate exact age in years, months and days between a birth date and any date, plus total days, weeks and the countdown to the next birthday.
BMI Calculator
Calculate your Body Mass Index from height and weight, in metric or imperial units, and see your WHO weight category instantly.
Break-Even Point Calculator
Find how many units you must sell to cover costs, from fixed costs, price per unit, and variable cost per unit. See break-even units and revenue instantly.
Compound Interest Calculator
Calculate the future value of your investments with compound interest. See how regular monthly contributions grow over time.
Discount Calculator
Calculate the sale price and amount saved from an original price and a percentage discount. Stack two discounts and see the effective discount rate.
Ecommerce Transaction Fee Calculator
See how much ecommerce platform transaction fees cost you per year — and how much you'd keep on a 0% platform. Compare Shopify, BigCommerce, WooCommerce and more.
Percentage Calculator
Work out percentages every way: X percent of Y, what percent X is of Y, and percentage increase or decrease. Fast, free, and 100% in your browser.
Profit Margin Calculator
Calculate gross profit, profit margin %, and markup % from your cost and selling price — or solve for the price you need to hit a target margin.
ROAS Calculator (Return on Ad Spend)
Calculate ROAS, break-even ROAS, and profit from your ad spend, revenue, and margin. See whether your ads are actually profitable, not just positive.
Sales Tax Calculator
Add or remove sales tax from any amount at any rate. Get the tax amount and the pre-tax and after-tax totals instantly, right in your browser.
Simple File Sharing
Share files directly between browsers using peer-to-peer WebRTC connections. No uploads, no servers — completely private.
Tip Calculator
Calculate the tip and total for any bill, then split it evenly across any number of people. Instant, private, and entirely in your browser.
Have a useful tool? You can contribute interactive calculators, converters, or utilities. See the contribution guide for how to submit your tool via GitHub Pull Request.