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Next due date

Next due date calculator

6 months from a date, 3 months from today, every 90 days from a date: enter the last done date and the interval.

When is it next due?

Calendar dates, not timestamps.

The day you last did the job.

Next due

Choose a date

The next five dates

    How the month-end rule works

    A month is added to the original date in one step, then the day is clamped to the length of the target month. 31 January plus one month is 28 February (29 in a leap year); plus two months it is 31 March, not 28 March. The app uses the same rule, so the calculator and the schedule maker agree.

    Days and weeks are whole calendar days. Daylight saving does not add or lose a day, and the result does not move with your time zone.

    What to use it for

    Use it for a warranty, a service, a filter, a treatment or any job with a fixed rhythm. If you want the job in a schedule with reminders, the schedule maker turns it into a repeat and a calendar file. If you are checking a warranty end date, the warranty calculator adds the status and the two reminder dates.

    Next due date questions

    How do I work out 6 months from a date?

    Enter the date as the last done date and set the interval to 6 months. The result is the same day six months later, clamped to the end of the month if that day does not exist. 31 August plus 6 months is 28 February, or 29 February in a leap year.

    How do I work out 3 months from today?

    Choose Today as the last done date and set 3 months. The result is today’s date three months later, with the same month-end rule.

    What does “every 90 days from a date” mean?

    Set the interval to 90 days. Days are counted as whole calendar days, so daylight saving does not add or lose a day.

    Why is 31 January plus one month 28 February?

    The app counts from the original date and clamps to the last day of the target month, rather than overflowing into March. It is the same rule as a monthly repeat in the app.

    Can I use it for a job that repeats every 6 weeks?

    Yes. Set the unit to weeks and the number to 6. The next five dates below the result show the rhythm.