Months Between Dates
Calculate the exact number of months and days between two dates.
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How to use this calculator
- 1
Select the start date.
- 2
Select the end date.
- 3
The result shows complete months plus remaining days, and the approximate decimal months.
Frequently asked questions
How are months calculated?
Complete calendar months are counted first, then remaining days are added. For example, Jan 15 to Apr 3 = 2 complete months + 17 days.
Why does decimal months use 30.44?
30.44 is the average number of days per month (365.25 ÷ 12). It accounts for months of different lengths across the year.
What is the difference between 1 month and 30 days?
A calendar month can be 28, 29, 30, or 31 days depending on the month and year. "1 month later" on Jan 31 = Feb 28/29 (28 or 29 days). "30 days later" = Mar 2/3.
How long is 18 months in years?
18 months = 1 year and 6 months = 1.5 years.
Months between dates: how it works
Calendar months vs fixed days
Calendar months are variable — February has 28 or 29 days; others have 30 or 31. This means "3 months from today" gives a different number of days depending on which months are involved. The calculator uses actual calendar month counting, not fixed 30-day approximations.
Common use cases for month calculations
Lease and rental periods, loan tenures (mortgage, car loan), subscription billing cycles, project milestones ("in 6 months"), medical protocols, warranty periods, and calculating how long someone has been employed.
Month fractions in finance
Many financial calculations (interest, depreciation) require fractional months. For example, a 14-month loan is 14/12 = 1.167 years. Knowing the precise number of months between dates is essential for pro-rata calculations.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →