Years Between Dates Calculator
Need the exact number of years between two dates, broken down into years, months and days? Enter a start and end date and this calculator walks the real calendar to give you the precise span. For a full breakdown with business days, see the date difference calculator.
Example
This breakdown is always calculated from the actual calendar span between the two dates. Unlike a plain day count, a years-and-days figure has no single well-defined "count both endpoints" adjustment, so there is no inclusive option here; if you need that distinction, the day count on the Date Difference Calculator has it.
From March 14, 1990 to July 2, 1994 is 4 years, 3 months and 18 days. For day-level detail on shorter spans, try the days ago calculator.
The full breakdown, not just whole years
The result gives years, months and days together, the way most of these questions are actually meant: not "4.3 years" but "4 years, 3 months and 18 days." The calculation walks the calendar from the earlier date to the later one, so a span crossing one or more leap years, or a February 29, still produces an exact figure rather than an approximation.
Frequently asked questions
Last updated: October 18, 2026
How this calculator works
This calculator computes the exact span between two dates using Gregorian calendar rules. Whole years are counted by anniversary: a full year passes only when the month and day come around again. Remaining months and days are counted from the real calendar, not from averages, so leap years and 28 to 31 day months are handled exactly. Decimal-year figures use the mean tropical year for conversion, and every calculation runs in your browser.
How to calculate years between dates
Manually counting years between dates is error-prone, especially across leap years and month boundaries. A dedicated years between dates calculator does the calendar math for you: enter any two dates and get the exact span in years, months, and days. Whether you're measuring employment tenure, a mortgage term, or the gap between historical events, this free years between dates calculator handles the tricky parts — February 29, varying month lengths, and inclusive versus elapsed counting — automatically. No spreadsheets, no mental arithmetic; just pick your dates and read the answer.
For the most precise results, always use the actual calendar dates rather than rounding to whole years. A quality years between dates calculator breaks the span into complete years first, then counts the leftover months and days — the same method courts and registries use for statutory periods. If your dates cross a leap year boundary, the calculation adjusts automatically. Bookmark this years between dates calculator for
Figuring out the number of years between dates sounds simple until you actually try it. Is it 16 years or 17? Do the leftover months count? What about the days? Questions like these come up when you check an age gap, mark an anniversary, measure a contract, or build a timeline. The years between dates calculator above answers them instantly. Enter a start date and an end date, and you get the exact difference in years, months, days, and decimal years, all at once.
The rest of this page explains what those numbers mean, how the math works, how to repeat it by hand or in a spreadsheet, and how leap years affect long date ranges. You will also find answers to the year questions people search for most, including how many years ago 2017, 2019, 2016, and 2009 were.
How the Years Between Dates Calculator Works
Three steps give you the answer. First, type the earlier date into the start field. Measuring back from today only? The years ago calculator is simpler. Second, type the later date into the end field. The order does not really matter, because the tool always reports a positive difference either way. Third, read the result. It appears the moment both dates are filled in.
The calculator returns the answer in four formats at the same time, since different tasks need different formats. You see the calendar breakdown in years, months, and days, the decimal year figure, the total month count, and the total day count. One calculation covers every version of the answer you might need, so you never have to convert between formats yourself.
Understanding the Results: Years, Months, Days, and Decimals
The four output formats each serve a different purpose. Here is what they mean, using one example throughout: January 15, 2010 to October 14, 2026.
| Format | Result for this example | Best used for |
|---|---|---|
| Years, months, days | 16 years, 8 months, 29 days | Anniversaries, age gaps, timelines |
| Decimal years | About 16.75 | Finance, statistics, prorated amounts |
| Total months | About 201 | Contract terms, loan schedules |
| Total days | 6,116 | Day counts, legal deadlines |
Years, months, and days
This is the calendar breakdown, the format people picture when they think about elapsed time. The method counts full year anniversaries first, then full months, then the leftover days. From January 15, 2010, sixteen full anniversaries bring us to January 15, 2026. Eight full months take us to September 15, 2026. The remaining stretch, September 15 to October 14, is 29 days. Put together: 16 years, 8 months, 29 days.
Decimal years
Decimal years express the same span as a single number. The calculator divides the total day count by 365.25, the average length of a year including leap years. For our example, 6,116 days divided by 365.25 gives about 16.75 years. Bankers, accountants, and analysts prefer this format because it plugs straight into formulas for interest, depreciation, and prorated charges.
Total months and total days
These are the raw counts with no breakdown. About 201 months, or exactly 6,116 days, between the two. Prefer weeks? The weeks between dates calculator counts those. dates. They come in handy when a contract says "24 monthly payments" or a policy sets a deadline in days.
How to Calculate Years Between Two Dates by Hand
The manual method follows the same logic the calculator uses. Work through it once and you will understand every number the tool shows you. Check the weekday of either endpoint with the day of week calculator.
- Step 1: subtract the years. Take the end year minus the start year. For 2010 to 2026, that is 16.
- Step 2: check whether the anniversary has passed. Compare the month and day of the end date with the month and day of the start date. October 14 comes after January 15 in the calendar year, so the 16th anniversary has already happened and the year count stays at 16. If the end date were December 20, 2025, the January 15 anniversary would not have arrived yet, and the answer would drop to 15 years.
- Step 3: count the leftover months. Subtract the start month from the end month: October (10) minus January (1) gives 9. Then check the days. Since the end day (14) is smaller than the start day (15), one month has not fully elapsed, so subtract 1. That leaves 8 months.
- Step 4: count the leftover days. Measure from the 15th of the month before the end date to the end date. September 15 to October 14 spans 29 days (15 days left in September plus 14 days in October).
The final answer: 16 years, 8 months, 29 days. Try the same steps with your own dates and compare against the calculator. The numbers will match.
Years Between Dates in Excel and Google Sheets
Spreadsheets handle this calculation well once you know the right formulas. These work in both Excel and Google Sheets, with your two dates in cells A1 (start) and B1 (end).
Full years, leftover months, and leftover days
The DATEDIF function accepts a unit code that controls what it returns:
=DATEDIF(A1, B1, "Y")returns full years. For our example, 16.=DATEDIF(A1, B1, "YM")returns the leftover months after full years. For our example, 8.=DATEDIF(A1, B1, "MD")returns the leftover days after full months. For our example, 29.
To combine them into one readable cell, join the three pieces:
=DATEDIF(A1,B1,"Y") & " years, " & DATEDIF(A1,B1,"YM") & " months, " & DATEDIF(A1,B1,"MD") & " days"
With A1 set to January 15, 2010 and B1 set to October 14, 2026, that formula prints "16 years, 8 months, 29 days". One detail: DATEDIF expects the start date first. Swap the order and you get an error.
Decimal years
For the single-number format, YEARFRAC does the job:
=YEARFRAC(A1, B1)
This returns about 16.75 for our example. YEARFRAC accepts an optional third argument that sets the day-count convention; the default works fine for general use, while finance teams sometimes specify basis 1 (actual/actual) for precision.
DATEDIF is technically undocumented in Excel, yet it has worked in every version for decades and Google Sheets supports it fully. If a formula ever returns a strange result, check that both cells hold real dates and not text that looks like a date.
Leap Years and Long Date Ranges
Leap years raise a fair question: does an extra February 29 change the year count? For the years figure, no. Years are measured by anniversaries, and anniversaries land on the same month and day regardless of how many leap days fell in between. Sixteen years is sixteen years whether the span held three leap days or four.
Leap days do change the day total, though. The sixteen years in our example contain four leap days (2012, 2016, 2020, 2024), which is why the total is 6,116 days instead of 6,112. The calculator counts every one of them automatically. Manual counters often forget this and land a few days short on long spans.
February 29 start dates deserve a note. If someone was born or an event occurred on February 29, the anniversary in a non-leap year has no exact match. Different tools resolve this differently, some using February 28 and others March 1. When a February 29 date matters to your calculation, run it through the calculator and check which convention the result follows.
Common Uses
People reach for a years-between-dates calculation in more situations than you might expect.
Age gaps. Subtract a parent's birth year from a child's, or compare two siblings, and you get the gap in exact years and months. Family historians use this constantly. A person's age is simply years between their birth date and today; the age calculator does it in one step. Comparing two people? The age difference calculator handles it.
Anniversaries and milestones. Wedding anniversaries, work anniversaries, and company founding dates all get measured this way. "How long have we been married?" is a years-between-dates question.
Historical timelines. Teachers and students measure the distance between events: subtract 1969 from the current year for the moon landing, 1989 for the fall of the Berlin Wall. Exact figures beat rounded guesses in any timeline.
Legal and statutory periods. Limitation periods, eligibility windows, and residency requirements are often expressed in whole years. An exact calculation avoids off-by-one disputes.
Financial terms. Bond maturities, fixed deposit terms, and long-running contracts all hinge on precise year counts. A day-level difference can shift interest calculations.
Contract and employment durations. Service length, lease terms, and vesting schedules are all expressed in years and months. HR departments and landlords live in these numbers.
Generational gaps. Researchers define generations by year ranges, and comparing a birth year against a generation boundary is a simple subtraction that benefits from the month-level precision the calculator provides.
Related Calculators
Days Ago Calculator: how many days have passed since any date.anniversaries, contract terms, and historical research — the answer is always one click away.
Years Ago Calculator: enter one past date and see how many years ago it was from today.
Months Between Dates Calculator: the same two-date difference measured in months.
Date Difference Calculator: full breakdown in years, months, weeks, and days.
Age Calculator: your exact age today in years, months, and days.