Days Since Calculator

How long ago was it, in every unit

The result above answers "how long ago" in whichever unit you need. The headline gives the exact day count. Underneath it, four figures cover the rest of the question:

• Calendar breakdown — years, months and days together, the way you would say it out loud ("2 years, 3 months and 10 days ago").
• Total months — the whole span expressed as one number of months, useful for anything billed or measured monthly.
• Full weeks — the exact number of complete weeks, for contexts that count in weeks rather than days.
• Day counting — whether the start date itself was counted, since that changes the total by one day either way.

The calendar breakdown is calculated from the actual calendar, not from an average month length, so a leap year or a run of short months never throws the months and days figures out of step with the day count above them.

Days since notable dates

As of today (September 23, 2026):

How to calculate days since a date

"Days since" means the number of complete days that have passed from a past date to today (or any chosen end date). The calculation is simple in principle: subtract the earlier date from the later date to get the number of days elapsed.

Elapsed days versus inclusive count

There are two conventions for counting days between dates:

• Elapsed days (default): The number of 24-hour periods that have passed. If you started something on January 1 and today is January 3, two days have elapsed. This is the standard for interest calculations, age, and most scientific contexts.
• Inclusive count: Count both the start and end date as days. January 1 to January 3 inclusive is 3 days. This is sometimes used in legal contexts where a period "from the 1st to the 3rd" means three calendar days.

This calculator shows elapsed days by default. The result is always the number of calendar days between the two dates, not counting the start date but counting the end date.

Day counting across years

For multi-year spans, the calculation must account for:

• Leap years (366 days instead of 365)
• The varying number of days in February specifically

A span from January 1, 2000 to January 1, 2024 crosses multiple leap years. The calculator handles all of this automatically.

Common uses for days-since calculations

• Personal milestones: How many days since you quit smoking, started a new job, moved to a new city, or got married.
• Fitness and health: Days into a diet, workout streak, sobriety, or medication course.
• Finance: Days since a loan was originated, a payment was last made, or an account was opened.
• Legal and regulatory: Days since a filing deadline, a contract was signed, or a statutory event occurred.
• Software and IT: Days since a system was last updated, a vulnerability was disclosed, or a backup was taken.
• Projects: Days since project kickoff, last release, or milestone completion.
• Real estate: Days on market, days since the last price change, or days since closing.

Converting days since to weeks, months, and years

Once you have the elapsed days, you can convert to other units:

• Weeks: divide by 7 (exact)
• Approximate months: divide by 30.44 (the average days per month)
• Approximate years: divide by 365.25 (accounts for leap years)

For exact years and months (rather than approximations), use the Date Difference Calculator which gives a breakdown in years, months, and days.

Why exact days matter

In many contexts, an approximate answer is not good enough:

• Interest accrual on a loan is calculated on exact calendar days, not approximate months.
• Employment probation periods in many countries are expressed in exact days (90 days, 180 days).
• Return and refund policies (30 days, 60 days) are measured from the day of purchase in exact calendar days.
• Clinical trials track elapsed days precisely for drug dosing and endpoint measurements.
• Court deadlines and statutes of limitations are often expressed in days, and missing by one day can have serious consequences.