Hey Product Hunt! 👋 I built this because I kept running into the same annoying problem: date math looks simple until you actually need it to be right. Months aren't the same length, leap years follow a rule almost nobody remembers, and daylight saving time can quietly throw off an hours calculation without any warning. So I built a calculator that gets those edge cases right instead of ignoring them — it even flags when a time you enter doesn't exist or happens twice because of a clock change. Three modes: find the difference between two dates or times, or add/subtract days, weeks, months, and years from a date. No sign-up, nothing to install, works instantly in your browser. Would genuinely love feedback, especially if you hit a calculation that looks wrong — that's exactly the kind of thing I want to know about.

Time and Date Calculator

Calculate date differences, or add and subtract time

Calculate date differences, or add and subtract time