Warranty Expiry Calculator

Features

• Purchase date + warranty length (months, years, days) → expiry as YYYY-MM-DD
• End-of-month clamping: 31 January plus one month is 28 February
• Leap-day handling: 2024-02-29 plus one year is 2025-02-28
• Days remaining, or how long ago it expired
• A verdict line: still covered, expired, or expires today
• A note when the date was clamped to month end, which you can turn off
• Pick the purchase date from the native calendar, no format to guess
• Everything runs on your device; the date never leaves the page

How to use

1. Open the picker and choose the purchase date
2. Enter the warranty length and pick months, years or days
3. The expiry date, days remaining and status appear at once
4. Use the copy button on a row to take the expiry date

FAQ

Why is 31 January plus one month not 3 March?

Because a warranty is not counted that way. The rule is “the same day next month, or the last day if there is none” — 31 January plus one month is 28 February (29 in a leap year). 3 March comes from handing “31 February” to a date library that rolls it over, which is a bug, not the rule.

Bought on a leap day with a one-year warranty — what date does it expire?

If the next year is also a leap year, 29 February; otherwise it clamps to 28 February. For example, 2024-02-29 plus one year is 2025-02-28.

Is it expired at “0 days left” or after one more day?

The expiry day itself is still covered (“expires today, the last day”); it counts as expired from the next day. That is the more common reading, for both sellers and buyers.