Software date validation
Leap-year checks are important when validating February dates, especially in forms, billing systems, travel tools, and calendars that must handle February 29 correctly.
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Leap Year Calculator
Check whether any year is a leap year using the Gregorian calendar rule, see year length and February length, and count leap years in a range. Useful for calendar logic, planning, software validation, and education.
Leap Year Calculator
Use this free leap year calculator to check whether any year is a leap year, see how many days are in the year, review February length, and count leap years in a range. It is useful for calendar math, scheduling, date logic, software validation, education, and planning. The tool also links naturally into the Date Difference Calculator, Days Until Calculator, and the wider Time & Date category.
Check leap years instantly
Enter a year to test the leap-year rule and optionally count how many leap years appear across a custom range.
Useful for
Calendar rules and date logic
Helpful for software checks, planning, education, and year-based scheduling.
The range count includes both the checked year and the range end year.
The calculator applies the Gregorian leap-year rule: divisible by 4, except centuries must also be divisible by 400.
Leap year result
Common Year
2026 has 365 days and February has 28 days.
2026 does not qualify as a leap year, so February stays at 28 days.
Previous leap year
2024
Next leap year
2028
Days in year
365
Leap years in range
3
Calculation steps
- 1Start with the year 2026.
- 2Check whether the year is divisible by 4.
- 3If it is also a century year, check whether it is divisible by 400.
- 42026 does not pass the leap-year rules, so it has 365 days and February has 28 days.
- 5The selected range contains 3 leap years.
How this tool works
The calculator applies the Gregorian calendar rule directly. Years divisible by 4 are usually leap years, but century years must also be divisible by 400. That means years like 2000 qualify while 1900 does not. If you need broader calendar comparisons after checking the year rule, continue with the Date Difference Calculator or the Days Until Calculator.
What this leap year calculator does
This tool checks whether a year is a leap year, explains the result, shows year length and February length, and gives nearby leap-year context. It also counts leap years inside a custom range for planning and reference.
Why leap years matter
Leap-year rules affect scheduling, payroll dates, subscriptions, software date validation, historical records, and long-range planning. A single extra day can change how timelines and date-based systems behave.
Leap year formula explained
Standard rule
Leap year if divisible by 4
Century correction
If divisible by 100, it must also be divisible by 400
Divisible by 4
Most years that divide evenly by 4 are leap years.
Divisible by 100
Century years are not leap years unless they also meet the 400-year rule.
Divisible by 400
Century years divisible by 400 remain leap years.
February 29
The extra leap-day appears in February during leap years.
Leap year calculator examples
Historical year rules
Years like 1900 and 2000 are common teaching examples because they show why the 100-year and 400-year correction rules matter in the Gregorian calendar.
Planning across ranges
If you are reviewing a decade or longer period, counting leap years in the range helps explain why some long date spans include extra days.
For broader date calculations, continue with the Date Difference Calculator. If you want a future event count from today, the Days Until Calculator is more appropriate. For weekday-only planning, use the Business Days Calculator.
Calendar workflows
Leap-year checks fit date validation, software testing, recurring billing, scheduling systems, educational examples, and long-range timeline planning where February length matters.
Responsive mobile layout
The page stays inside a max-width container with responsive cards and input spacing so the calculator remains readable on phones, tablets, and desktop screens.
Time & Date category fit
A leap-year calculator belongs in Time & Date because it explains a core calendar rule that affects date math, event timing, and real-world scheduling logic.
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Frequently asked questions
A leap year has 366 days instead of 365 because February gets an extra day. This keeps the calendar aligned with the Earth's orbit around the Sun.
Explore This Tool in Context
Leap Year Calculator is part of the Time & Date collection. If you want a broader view of similar workflows, open the Time & Date category page or browse all QuickTools categories.
Common next steps after this tool include Date Difference Calculator, Time Zone Converter and Time Duration Calculator.
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