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Months Between Dates Calculator

Count the months between two dates the way people normally mean it: whole calendar months, then the days left over. A decimal figure based on the average month length is given for calculations.

Quick examples
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Months between8 months, 26 days
Whole months
8
Months (decimal, 30.44-day average)
8.84
Years, months, days
8 months, 26 days
Days
269

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      Formula

      Whole months = calendar months completed between the dates
      Decimal months = days between ÷ 30.44 (average month length)

      How to use it

      1. Enter the start and end dates.
      2. Read whole months and remaining days, or the decimal for pro-rating.

      Worked examples

      January 15, 2025 to October 11, 2026

      Months between
      20 months, 26 days
      Whole months
      20
      Years, months, days
      1 year, 8 months, 26 days

      March 1, 2026 to March 1, 2027

      Months between
      12 months
      Days
      365

      Why there are two answers

      A month is not a fixed number of days, so “months between” has no single exact value. Leases, subscriptions and ages use calendar months. Pro-rated charges and interest often use days divided by an average month of 30.44 days (365.25 ÷ 12). Use the figure that matches the rule you are applying.

      Questions people ask

      How many months is 90 days?

      About 2.96 average months — just under three. In calendar terms it depends on the months involved.

      How many months between two dates in different years?

      Multiply the difference in years by 12 and add the difference in months, then subtract one if the end day is earlier in the month than the start day.

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