Tools
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.
Temperature Converter
Convert temperatures between Celsius, Fahrenheit and Kelvin instantly. Type a value in any field and the other two update live, negatives and decimals included.
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.
Word & Character Counter
Count words, characters, sentences, and paragraphs as you type — with a reading-time estimate. Runs 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.