Time calculators

Year Calculator

Updated Jul 30, 2026 By Jehan Wadia
Rate Formulas
Calendar & Fiscal Settings
All dates you type are read in this calendar; the other calendar's equivalent is shown too.
Adds fiscal-year results to the difference and future/past modes.
Used only while Fiscal Year Mode is on.
Active calendar: Gregorian
Today: —
Full dates give exact months and days.
Read in the active calendar system.
May be before or after the start date.

Results

Step-by-Step Solution
Chart

Introduction

The Year Calculator helps you work with years fast. Type in two dates and it tells you how many years, months, and days sit between them. It also counts the total weeks and days, so you get the full picture. For a breakdown that focuses on days and months instead of years, try the Date Duration Calculator.

This tool has six modes. You can find the year difference between two dates, jump ahead or back with years from now or years ago, find an age in years, check if a year is a leap year, get a year range summary, or build a bulk year table around any base year.

You can pick the Gregorian or Julian calendar, and turn on fiscal year mode if your work year does not start in January. Every answer comes with clear result cards, a step-by-step solution, and a chart. Change any field and the numbers update right away.

How to use our Year Calculator

Pick a mode, type your dates or years, and the year calculator shows the years between them, plus months, weeks, days, leap years, and a step-by-step solution.

Calendar System: Choose Gregorian (the one most people use) or Julian. Your dates are read in this calendar, and the other calendar's date is shown too. If you work with astronomical day numbers, the Julian Date Calculator goes deeper.

Fiscal Year Mode: Turn this on if you count years for business or budgets instead of January to December.

Fiscal Year Starts In: Pick the month your fiscal year begins. This only works when Fiscal Year Mode is on.

Mode tabs: Click a tab to pick what you want: Year Difference, Years From Now / Ago, Age in Years, Leap Year Checker, Year Range Summary, or Bulk Year Table.

Input Precision (Year Difference): Choose full dates for exact months and days, or years only for a quick answer.

Start Date / Start Year: Type the first date as MM/DD/YYYY, or just the year if you picked years only.

End Date / End Year: Type the second date or year. It can be before or after the start.

Swap button: Click it to flip the start and end values.

Number of Years: In the From Now / Ago mode, type how many years to move, like 25. To shift by days or months instead, use the Date Add Calculator or the Add Days Calculator.

Direction: Choose From Now to go forward in time, or Ago to go back. The Days Until Calculator and Days Ago Calculator answer the same question in days.

Reference Date: Type the date you want to count from, or click Today to use today's date.

Input Precision (Age): Choose a full birth date for an exact age and birthday countdown, or just the birth year. Our full Age Calculator adds even more detail, and the Birth Year Calculator works backward from an age.

Birth Date / Birth Year: Type when you were born. It must be on or before the "Age As Of" date.

Age As Of: Type the date you want the age figured for, or click Today. To compare two people, see the Age Difference Calculator.

Year to Check: In the Leap Year Checker, type one year to see if it has 366 days.

Count Leap Years From / To: Type a start year and end year to count all leap years in that range.

Start Year / End Year (Year Range Summary): Type two years to see the years, days, weeks, decades, and centuries in between. The Weeks Calculator and Month Calculator zoom in on those smaller units.

Base Year: In the Bulk Year Table, type the year you want the table built around.

Range Around Base: Pick ±10, ±25, or ±50 years to set how many rows the table shows.

Calculate and Reset: Click Calculate to see your results, or Reset to put every field back to its default.

What Is a Year?

A year is the time it takes Earth to go once around the Sun. That trip takes about 365.2425 days. Since a calendar can only use whole days, most years have 365 days, and some have 366. The extra day keeps our dates lined up with the seasons.

Leap Years

A leap year has 366 days. The extra day is February 29. In the Gregorian calendar, the rule has three parts:

  • If the year divides evenly by 4, it is a leap year.
  • But if it divides evenly by 100, it is not.
  • Unless it also divides evenly by 400 — then it is.

So 2024 and 2000 were leap years. 1900 and 2100 are not. Leap years come about 97 times every 400 years. The older Julian calendar used a simpler rule: every 4th year was a leap year. That made the calendar drift about 3 days every 400 years, which is why most of the world switched to the Gregorian calendar. If you want to see the divisibility math on its own, the Modulo Calculator shows each remainder.

Counting Years Between Two Dates

There are two ways to count years, and they give different answers:

  • Years spanned: subtract one year from the other. From 1900 to 2000 is 100 years.
  • Years counted (inclusive): include both end years. From 1900 to 2000 is 101 years.

Full dates matter too. Someone born on December 1, 2000 is not 25 years old on January 1, 2025. Their birthday has not come yet, so they are still 24. That is why age is counted from the month and day, not just the year. When you need only working days inside a span, switch to the Business Days Calculator, and for hours and minutes use the Time Duration Calculator.

Calendar Years vs. Fiscal Years

A calendar year runs from January 1 to December 31. A fiscal year is a 12-month period a business or government uses for its money records, and it can start in any month. For example, many governments start their fiscal year in October or April. If a fiscal year starts in July, then July 2026 through June 2027 is one fiscal year. Fiscal years also shape payroll and leave tracking, which is where the PTO Accrual Calculator and Annual Leave Calculator come in handy.

Decades, Centuries, and Eras

A decade is 10 years, like the 1990s. A century is 100 years. The 21st century covers the years 2001 through 2100, because counting started at year 1, not year 0. Eras are longer stretches of history with names, like the Medieval Period or the Modern Era.

Handy Year Facts

  • 1 common year = 365 days = 52 weeks and 1 day = 8,760 hours
  • 1 leap year = 366 days = 52 weeks and 2 days = 8,784 hours
  • 1 year = 12 months = 4 quarters
  • Average year length = 365.2425 days
  • A date moves ahead 1 weekday each common year, and 2 weekdays across a leap day

Need to turn weeks into months for a pregnancy or project timeline? The Weeks to Months Calculator handles that conversion.

Where Year Math Is Used

People count years to find an age, plan a retirement date, check a warranty or loan end date, work out how long ago a historic event happened, or line up school and tax deadlines. Getting leap years right keeps those answers correct, especially over long spans. Year counts also feed straight into money math: the Compound Interest Calculator and CAGR Calculator both need a year figure, the Inflation Calculator compares prices across years, the Amortization Calculator spreads a loan over a set number of years, and the Retirement Calculator uses the years left before you stop working. For job-history spans, the Tenure Calculator and Deadline Calculator are good companions.

Formulas used

Julian Day Number from a Gregorian date
\text{JDN} = d + \left\lfloor \frac{153m' + 2}{5} \right\rfloor + 365y' + \left\lfloor \frac{y'}{4} \right\rfloor - \left\lfloor \frac{y'}{100} \right\rfloor + \left\lfloor \frac{y'}{400} \right\rfloor - 32045,\quad a = \left\lfloor \frac{14-m}{12} \right\rfloor,\ y' = y + 4800 - a,\ m' = m + 12a - 3
Total days between two dates
\text{Days} = \left| \text{JDN}_{\text{end}} - \text{JDN}_{\text{start}} \right|
Years, months, days breakdown (with borrowing)
Y = y_2 - y_1,\quad M = m_2 - m_1,\quad D = d_2 - d_1;\quad D < 0 \Rightarrow M \mathrel{-}= 1,\ D \mathrel{+}= \text{DaysInMonth}(m_2 - 1);\quad M < 0 \Rightarrow Y \mathrel{-}= 1,\ M \mathrel{+}= 12
Total months, weeks and decimal years
\text{Months} = 12Y + M,\qquad \text{Weeks} = \left\lfloor \frac{\text{Days}}{7} \right\rfloor,\qquad \text{Years}_{\text{dec}} = \frac{\text{Days}}{365.2425}
Leap year test (Gregorian and Julian)
\text{Leap}_{G}(y) \iff (y \bmod 4 = 0 \ \text{and}\ y \bmod 100 \neq 0)\ \text{or}\ y \bmod 400 = 0,\qquad \text{Leap}_{J}(y) \iff y \bmod 4 = 0
Count of leap years in a year range
L(n) = \left\lfloor \frac{n}{4} \right\rfloor - \left\lfloor \frac{n}{100} \right\rfloor + \left\lfloor \frac{n}{400} \right\rfloor,\qquad \text{Leaps}(a,b) = L(b) - L(a-1)
Years from now / years ago (target date)
y_{\text{target}} = y_{\text{base}} \pm n,\qquad d_{\text{target}} = \min\left(d_{\text{base}},\ \text{DaysInMonth}(y_{\text{target}}, m_{\text{base}})\right)
Range summary: span, inclusive count, days and century
\text{Span} = b - a,\quad \text{Inclusive} = b - a + 1,\quad \text{Days} = 365\,N_{\text{common}} + 366\,N_{\text{leap}},\quad \text{century}(y) = \left\lfloor \frac{y-1}{100} \right\rfloor + 1

Frequently asked questions

Why does the calculator say 6 years instead of 7 when the years look 7 apart?

The tool counts full years, not just the year numbers. From January 15, 2020 to July 30, 2026 the year numbers differ by 6, and the extra months and days show as "plus 6 months and 15 days." A full year only counts once the same month and day come around again.

What is the difference between years spanned and years counted?

Years spanned is simple subtraction. Years counted adds 1 because both end years are included.

  • 1990 to 2000 spanned: 10 years
  • 1990 to 2000 counted: 11 years

Use spanned for age or duration. Use counted when you need a list of every year.

Can I enter the end date before the start date?

Yes. The Year Difference mode reads it as elapsed time and gives a positive answer either way. The badge still tells you if your end date is in the past or future. Click Swap if you want the fields flipped.

What does the Years (Decimal) result mean?

It is the total days divided by 365.2425, the average length of a year. So 2,388 days is about 6.5378 years. Use this number for finance math like interest or growth rates, where a decimal year works better than years, months, and days.

What happens if I add years to February 29?

The day is pulled back to February 28 when the target year has no leap day. The result card tells you the day was adjusted. Example: February 29, 2024 plus 1 year gives February 28, 2025.

Why is my age still one year lower than I expected?

Your birthday has not happened yet in that year. Age only goes up on the birthday itself, not on January 1. Check the Next Birthday card to see how many days are left and what age you will turn.

What does Age in Years show if I only know my birth year?

Pick Birth year only and the tool uses January 1 of that year. The age can be up to one year too high for part of the year. Use a full birth date when you need the exact number.

Which years are leap years in the Julian calendar?

Every year that divides by 4, with no exceptions. So 1900 and 2100 are leap years in the Julian calendar but not in the Gregorian one. Switch the Calendar System dropdown to Julian and the leap checker uses that simpler rule.

Why do the Julian and Gregorian dates not match?

The two calendars count leap years differently, so they slowly drift apart. Today the gap is 13 days. The result cards show your date in both calendars so you can compare them side by side.

How do I count how many leap years are in a range?

Open the Leap Year Checker tab and fill in "Count Leap Years From" and "To." You get the total, the percent of years in the range that are leap years, and a chip list of each leap year.

What does FY 2026/27 mean in the results?

It is a fiscal year that starts in one calendar year and ends in the next. If your fiscal year starts in July, then July 2026 through June 2027 is FY 2026/27. When the fiscal year starts in January, the label is just "FY 2026."

Do I have to turn on Fiscal Year Mode?

No. Leave it off for normal January-to-December years. Turn it on only when you need fiscal year labels and fiscal year counts added to the Year Difference and From Now / Ago results.

What year range does this calculator accept?

Years 1 through 9999. If a shift would land outside that range, you get an error message telling you which year it tried to reach. BC years are not supported.

What date format should I type?

MM/DD/YYYY, like 07/30/2026. Dashes and dots also work, and YYYY/MM/DD is accepted. If the day does not exist in that month, the tool tells you how many days that month has.

Why does the century number seem one higher than the year?

Counting started at year 1, not year 0. So the 21st century runs from 2001 to 2100, and 2026 falls in it. The tool uses this standard rule for every century label.

What is the Bulk Year Table for?

It lists every year around a base year with the gap in years, whether it is before or after, leap year status, and century. It is handy for quick lookups, like finding which birth year matches a certain age or scanning leap years near a date.

How many leap days will I live through?

The Age mode counts them for you in the Leap Days Lived Through card. It only counts February 29ths that fall between your birth date and the as-of date, so a leap year you were born in late does not count.

Does the calculator show the day of the week?

Yes. The From Now / Ago mode shows the weekday of the result, and the Age mode shows the weekday you were born. The Year Difference mode shows the weekday for both dates.

Why do the total months and total days not divide evenly?

Months have 28 to 31 days, so they are not all the same size. The tool counts whole calendar months first, then the leftover days. That is why 6 years, 6 months, and 15 days is 78 months plus 15 extra days.

What are milestone birthdays in the results?

Common landmark ages like 16, 18, 21, 30, 50, 65, and 100. The Age mode shows the next one, how many years away it is, and the exact date it falls on, so you can plan ahead.

Do I need to click Calculate every time?

No. Results update as soon as you change a field or switch tabs. The Calculate button is there if you want to refresh the answer yourself, and Reset puts every field back to its default.

Related Time calculators

All Time calculators
Time

Add Days Calculator

Add or subtract years, months, weeks, and days from any date. Skip weekends and US holidays in business days mode. Custom holidays and breakdown chart.

Open Time

Age Calculator

Use our free age calculator to find your exact age in years, months, weeks, and days. Enter your birthdate and instantly calculate your precise age.

Open Time

Age Difference Calculator

Calculate age differences in years, months, weeks, days, hours, and seconds. Enter birthdates, birth years, or direct ages. Half-plus-seven rule and steps.

Open Time

Birth Year Calculator

Estimate your birth year from your age in years, months, weeks, days, hours, minutes, or seconds. Shows Chinese zodiac, generational cohort, and timeline.

Open Time

Business Days Calculator

Count business days between two dates or add and subtract working days from a start date. Exclude weekends, public holidays for 10 countries, and custom holidays.

Open Time

Date Add Calculator

Add or subtract years, months, weeks, days, hours, and minutes. Toggle business days with US holiday exclusions and custom holidays. Step-by-step included.

Open Time

Date Calculator

Calculate days between two dates with year, month, week breakdowns. Add or subtract years, months, weeks, days. Exclude weekends and US federal holidays from business day counts.

Open Time

Date Duration Calculator

Calculate the exact duration between two dates in days, weeks, months, and years. Free online date duration calculator for quick and accurate results.

Open Time

Days Ago Calculator

Find the exact date any number of days ago. Get weekday, week of year, quarter, season, and business days. Includes step-by-step solution and chart.

Open Time

Days From Date Calculator

Calculate a future or past date by adding or subtracting calendar or business days. View step-by-step math, ISO week, quarter, and a span breakdown chart.

Open Time

Days From Today Calculator

Calculate future or past dates by calendar or business days. Skips weekends and U.S. federal holidays. Includes ISO week, milestones, and timezone support.

Open Time

Days Since Calculator

Calculate days since or until any date. Filter by business days, see breakdown in weeks, months, and years, track milestones, and view a live counter.

Open Time

Days Until Calculator

Use our free Days Until Calculator to find out how many days are left until any date. Count down to birthdays, holidays, deadlines, and special events instantly.

Open Time

Deadline Calculator

Count calendar or business days forward or backward from any date. Skips weekends and federal or state holidays. Includes rollover and skipped day details.

Open Time

ETA Calculator

Calculate arrival time, required speed, or departure time with stops, traffic buffer, and time zones. Supports multi-segment routes and task progress mode.

Open Time

Julian Date Calculator

Convert calendar dates, Ordinal Julian Dates (yyddd), and Julian Day Numbers. AD/BC eras, Julian and Gregorian calendars, MJD, and two-date intervals.

Open Time

Month Calculator

Calculate months and days between two dates. Get total weeks, hours, minutes, business days, weekend days, and percentage of a calendar year with charts.

Open Time

Tenure Calculator

Calculate loan repayment tenure from EMI and interest rate. Measure service duration between dates or find group average tenure. Step-by-step solutions.

Open Time

Time Difference Calculator

Calculate the exact time difference between two times or dates. Free online time difference calculator shows hours, minutes, and seconds instantly.

Open Time

Time Zone Calculator

Convert time between 38 global time zones. Enter date, HH:MM:SS, and source/destination zones. Get UTC offset breakdown, day change detection, and offset comparison chart.

Open Time

Time Zone Difference Calculator

Compare up to 3 time zones with DST-aware offsets on any date. Search by city or IANA name, toggle 12/24h format, view step-by-step math and UTC chart.

Open