How Long Is That in Weeks and Months?
Enter the number of days between your two dates to instantly convert to weeks and months — for deadlines, countdowns, and project planning.
An average month is 30.44 days — not 30. Using 30 introduces a 5-day error over a full year.
30.44
average days per month (365.25 ÷ 12) — used for accurate month conversions
365.25
average days in a year accounting for leap years every 4 years
52.18
weeks in a year — slightly more than 52 due to the 0.25-day leap year average
Thinking about time more clearly
Use for project deadlines
When planning a project, convert your timeline into weeks and months to communicate with stakeholders more naturally. '90 days' is harder to visualise than '13 weeks' or '3 months'. Use this calculator to translate any day count into whichever unit makes your deadline most intuitive.
Countdowns and milestones
Weddings, due dates, visa expirations, contract renewals — any milestone can be expressed in days. Converting to months gives a gut-feel sense of urgency: 180 days sounds far away; 6 months feels real. Use both perspectives for planning and motivation.
Why average month length matters
Using 30 days/month introduces cumulative error. Over a year, 12 × 30 = 360 days — 5 days off. Using 30.44 (the true average) keeps calculations accurate. The difference matters for contracts with 'monthly' billing cycles, subscription proration, and interest calculations that compound monthly.
How the Time Between Dates Calculator Works
Formula
Weeks = Days ÷ 7\nMonths = Days ÷ 30.44Enter the total number of days in your date range. The calculator divides by 7 for weeks and by 30.44 (the average calendar month length — 365.25 ÷ 12) for months.
Results are shown as decimals so you can see partial weeks and months. Round down for full completed units, or use the decimal for proportional calculations.