Date Difference Calculator
Pick a start and end date. We show calendar days, whole weeks, and an approximate month count (30.44-day average month — not the same as “calendar months”).
Inputs
Results
Days between
Reading the numbers
Days use midnight-to-midnight UTC-neutral local dates in your browser. Weeks are whole 7-day blocks inside that span. Approximate months divide the day count by 30.44 — handy for rough duration, not for legal “one calendar month” rules.
Frequently asked questions
How are days between two dates counted?
We take the absolute difference between the two selected local calendar dates in whole days. If you check inclusive mode, we add one day so both endpoints count.
Why do approximate months use 30.44 days?
Averaging month length (about 365.25/12) gives a quick sense of scale. It is not the same as counting calendar months, which vary from 28 to 31 days.
How are whole weeks calculated?
Whole weeks are the number of complete 7-day blocks that fit inside the day span after your inclusive or exclusive choice.
Does time zone affect the result?
We use date-only fields in the browser’s local calendar, so there is no time-of-day component—only the dates you pick matter.
What if the end date is before the start date?
We still show the absolute span in days and note in the hint that the end is before the start.
Are my dates sent to a server?
No. The tool runs locally with JavaScript and does not require signup.