Date difference calculator
This free tool calculates the difference between two dates and shows the result in days, weeks and approximate months. Pick a start and end date — handy for planning, working out deadlines, or counting the time since an event.
How the calculation works
The calculator subtracts the start date from the end date to give the result in whole days. It then divides the days by 7 for weeks and by roughly 30.44 for months. Everything runs in your browser and is exact to the day.
Worked example
Between 1 January and 31 December the difference is 364 days, about 52 weeks and ~12 months. The result appears instantly for any two dates.
Frequently asked questions
How are months counted?
The number of days is divided by the average month length (30.44 days) for an estimate.
Is the result accurate?
Days are exact; months are approximate based on the average.
Is my data stored?
No — the calculation runs in your browser.
Is the tool free?
Yes — completely free.