Date Difference Calculator

Counting days between two calendar dates answers return windows, project timelines, pregnancy tracking companions, and "how long until vacation?" questions. The core number is total calendar days between the endpoints; weeks are total days ÷ 7, and month/year approximations use averages for quick mental math — not legal precision.

Store policies differ on inclusivity. "30 days from purchase" might mean the purchase day is day 1, or the clock starts the next day. Contract law may count business days only. This tool reports the raw calendar span — read the fine print on the policy you are matching.

Example: January 1, 2026 to July 30, 2026 spans 210 days (~30 weeks, ~7 months approximate). A 90-day software trial starting March 1 ends May 30 if day 1 is March 1 and you count 89 additional days — verify whether the vendor uses inclusive counting.

Common mistakes include confusing calendar days with business days, assuming every month has 30 days for deadline math, and forgetting timezone boundaries when dates cross midnight internationally (this tool is date-only).

Leap day birthdays celebrate on February 28 or March 1 in non-leap years for parties — legal age for licenses still follows statute, which this tool calculates from actual calendar dates.

Software trial expirations often say "14 days" from install — confirm whether install day counts; compare install date to today with this tool.

Warranty periods from delivery date use the same day-count logic — enter delivery as start and today as end for "is warranty still active?" checks.

Subscription renewals billed annually show "renews in 342 days" on account pages — match those dates here to see months remaining.

Limits: approximate months and years are rounded for readability. For court deadlines or ISO 8601 durations, use the exact day count and official rules, not the month estimate alone.