How it's calculated
months = (Y₂ − Y₁) × 12 + (M₂ − M₁), minus 1 if end day < start day
Y, M, D = year, month, day of each date. Counts whole calendar months only; a partial final month is dropped by borrowing a month when the end day falls earlier than the start day.
Common questions
How are full months counted?
The tool counts each completed month from the start date. Leftover days that do not make a whole month are shown separately.
Why use this for a lease or loan?
Lease terms, loan periods, and pension credit are usually billed in whole months, so the exact month count matters more than the raw day total.