Months Between Two Dates
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About this calculator
Estimate the number of months between two dates. Because calendar months vary in length (28–31 days), the result uses the average month length of 30.44 days. For exact month counts, the result is shown in days first — divide by 30.44 for approximate months.
How it works
The calculator computes the difference in days between the two dates and presents it in your selected unit. To convert the day count to months, divide by 30.44 — the average number of days in a month (365.25 ÷ 12). This averaging approach is necessary because calendar months range from 28 to 31 days, so there is no single exact conversion factor.
When to use this calculator
Landlords and tenants calculate lease durations in months. Subscription services determine billing periods. HR departments compute notice periods and probation lengths. Financial planners estimate investment horizons. Job seekers calculate employment gaps for resume accuracy. Visa applicants determine how many months remain on their authorized stay.
Examples
From January 15 to July 15 is 6 calendar months, or about 181 days.
Because months vary from 28 to 31 days, a span you would call "3 months" can be anywhere from 89 to 92 actual days.
Common spans in days
How long familiar date ranges are when measured in days:
| Date range | Days |
|---|---|
| One week | 7 |
| One month (avg) | 30.4400 |
| One year | 365.250 |
| One decade | 3,652.5 |
Frequently asked questions
How is a month counted here?
The calculator counts real days, which you divide by the 30.44-day average for approximate months. For exact calendar months, compare the day-of-month and month fields of the two dates directly.
Why isn't the month count exact?
Calendar months have different lengths (28–31 days), so there is no single fixed number of days per month. The 30.44-day average smooths this out.
How many months is 100 days?
About 3.3 months (100 ÷ 30.44).