Password change reminder
Work out how long a password has been in use, how many days are left, when it expires and whether to rotate it — from a date you provide, with no system clock involved.
Runs in your browserEvery computation happens in your browser — your data never leaves this device.
Reminder settings
Result
Enter the last change date to see the days in use and the advice.
Day counts subtract UTC day numbers, so time zones and daylight saving never affect them. The tool reads no clock, makes no requests and stores none of the dates you type.
What this tool does
- Your company forces a password rotation every 90 days — enter the last change date to see how many days are left before you get locked out.
- Audit a password manager: sort accounts by days remaining and rotate the most overdue ones first.
- Answer a compliance question about a 90-day policy with concrete day counts instead of a guess.
- Set “today” to any past date to see how long a password had been in use at that moment.
Example
Input
Last changed 2026-07-01, today 2026-10-10, policy 90 days, warn 7 days ahead
Output
Days in use 101, days remaining −11, due date 2026-09-29, used share 112.2%, status “Expired”, advice “Change it now”
A negative remaining value means it expired 11 days ago. The due date is simply last-changed plus the policy length, not a month-based calculation.
Frequently asked questions
Why can the remaining days be negative?
A negative value tells you how far past the due date you are: −11 means 11 days overdue. That is more useful than a flat “expired” label because you immediately see whether it just lapsed or has been ignored for a while.
What is the difference between “due today” and “expired”?
A remaining value of 0 counts as due today: it is still inside the policy window but must be handled today. Only a negative value is expired. Both recommend changing immediately, they just read differently.
What should I enter for the warning window?
Seven days means you get an “expiring soon” status while 7 or fewer days remain. Zero means only the due date itself warns you. It must be no larger than the policy length, otherwise it is meaningless and the tool rejects it.
How are the days counted — does my time zone matter?
Both dates are converted to day numbers since 1970-01-01 and subtracted, using the UTC calendar day, so no time zone or daylight saving shift can turn a day into 23 or 25 hours. Month, year and leap-year boundaries are handled by the calendar.
Are the dates I type stored anywhere?
No. The calculation runs entirely in your browser, the page makes no requests, and a refresh clears everything. The password itself is never needed here — only the dates.
Keywords：password rotationpassword expirycredential policydays remainingsecurity hygiene密码更换密码过期已用天数剩余天数密码策略