What Is a Leap Year?

Learn How Leap Years Keep Our Calendar Accurate

December 30, 2020
29 Leap Year Fence

Leap years keep our calendars in check! Allow us to explain why leap years are necessary and share some of the fun folklore surrounding them. 

What Is a Leap Year?

Simply put, a leap year is a year with an extra day—February 29—which is added nearly every four years to the calendar year.

Why Are Leap Years Necessary?

Adding an extra day every four years keeps our calendar aligned correctly with the astronomical seasons, since a year according to the Gregorian calendar (365 days) and a year according to Earth’s orbit around the Sun (approximately 365.25 days) are not the exact same length of time. Without this extra day, our calendar and the seasons would gradually get out of sync. (Keep reading for a longer explanation.) 

Because of this extra day, a leap year has 366 days instead of 365. Additionally, a leap year does not end and begin on the same day of the week, as a non–leap year does.

How Do You Know If It’s a Leap Year?

Generally, a leap year happens every four years, which, thankfully, is a fairly simple pattern to remember. However, there is a little more to it than that.

Here are the rules of leap years:

  1. A year may be a leap year if it is evenly divisible by 4.
  2. Years that are divisible by 100 (century years such as 1900 or 2000) cannot be leap years unless they are also divisible by 400. (For this reason, the years 1700, 1800, and 1900 were not leap years, but the years 1600 and 2000 were.)

If a year satisfies both the rules above, then it is a leap year. 

When Is the Next Leap Year?

Leap Year Leap Day
2024 Thursday, February 29
2028 Tuesday, February 29
2032 Sunday, February 29
2036 Friday, February 29

Why Do We Need Leap Years?

The short explanation for why we need leap years is that our calendar needs to stay aligned with the astronomical seasons.

One orbit of Earth around the Sun takes approximately 365.25 days—a little more than our Gregorian calendar’s nice, round number of 365. Because the calendar does not account for the extra quarter of a day that the Earth requires to complete its orbit around the Sun, it doesn’t completely align with the solar year. 

Because of this .25 difference, our calendar gradually gets out of sync with the seasons. Adding an extra day, aka a “leap day,” to the calendar every 4 years brings the calendar in line and therefore realigns it with the seasons.

Without leap days, the calendar would be off by 5 hours, 48 minutes, and 45 seconds more each year.

After 100 years, the seasons would be off by 25 days! Eventually, the months we call February and March would feel like summer months in the Northern Hemisphere.

The extra leap day adjusts this drift, but it’s not a perfect match: Adding a leap day every four years overcompensates by a few extra seconds each leap year, adding up to about three extra days every 10,000 years. 

What Is a Leap Day? And a Leapling?

A “leap day” is the extra day in the leap year: February 29.

A “leapling” is a person born on a leap day. Any leap day babies out there? We’d love to hear from you in the comments below!

Leap Year Facts and Folklore

  • Ages ago, Leap Day was known as “Ladies Day” or “Ladies’ Privilege,” as it was the one day when women were free to propose to men. Today, Sadie Hawkins Day sometimes applies to Feb 29 (leap day), based on this older tradition.
  • According to folklore, in a leap year, the weather always changes on Friday.
  • “Leap year was ne’er a good sheep year” (old proverb)

Are Leap Years Bad Luck?

Many feel that to be born on Leap Day, thereby becoming a “leapling,” is a sign of good luck.

In some cultures, it is considered bad luck to get married during a leap year.

We don’t know of any evidence supporting that marriage theory, but we do know that during leap years:

  • Rome burned (64),
  • and the Titanic sank (1912).

By the same token, also in leap years:

  • the Pilgrims landed at Plymouth, Massachusetts (1620),
  • Benjamin Franklin proved that lightning is electricity (1752),
  • and gold was discovered in California (1848).

Do you have any leap year memories? Are you a Leapling yourself? Please share in the comments below!


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Reader Comments

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RE: Leap Year Memories...

I'd like to leap out of 2020 with no recollection of this year!

1 year contract

When cell phones​ were just starting to become common place in the 90's I signed up for a new cell plan with a one year contract. The sales lady told me that because it was a one year contract I couldn't​ cancel early without paying a penalty, but if I cancelled after the date i started I'd get charged for another month. She said, "So if you don't want to renew you have to cancel on this exact date next year." Since it was leap day I was like, "But this day doesn't exist next year!" She looked at me like I was crazy. When I explained that it was leap day she seemed shocked. I just wanted to know if I should cancel on February 28th or March 1st. She had to ask the manager and everyone in the store. When nobody knew, they called corporate. A half hour later she tells me nobody seems to know the answer to your question because it's never happened before, but we'll call you when we find out. Nobody ever did. I ended up trying to cancel on March 1 and it was a whole thing all over again. Eventually they decided to give me a month free and cancel the contract in April. The lesson I learned is never sign a contract on leap day. LoL


Really? You don't know for sure?

Leap Year definition

The Editors's picture

The explanation is provided in the above article. There are rare exceptions to the every-four-year rule. So, you could say Leap Year is every 4 years … until it’s not. 

Leap year

I’m a leap year baby. Born February 29th, 1972. I celebrate my off years 12 noon on the 28th till 12 noon March 1st. I love my special day!!!

Leapling daughter

Our daughter is a Leapling! She will be 4 years old this year (Sweet sixteen!). My original due date was for March 1. We celebrate her birthday from noon on the 28th to noon on the 1st during non leap years.

Leap year 2020

My husband & I got a divorce in 1983. But February 29, 1984 I asked him to marry me & he said yes but I also had to give him $50,000! Ha! Ha! Of course he was kidding. But we had to barrow the money to get the license & get to the courthouse in Memphis, TN. To our surprise the news crew from channel 13 in Memphis was there & we were on the news & they mentioned about Sadie Hawkins day. I have tried to find that news clip to no avail. My husband passed away June 29, 2018. Our first marriage was August 26, 1974 (my 17th birthday also). So on that date in 2018 we would have been married 44 years. I still miss him so much! The love of my life - my soulmate forever!

Sadie Hawkins Anniversary

My husband and I got married on leap day 1996. But I wouldn't use it as proof either way of luck.

I will be 16 tomorrow!

I was born on Feb. 29th in 1956. I will celebrate my 16th leap birthday tomorrow. Growing up, I always celebrated my birthday on February 28th because that was my mom's birthday. We enjoyed sharing our birthday on non-leap years. Happy Birthday to all leaplings out there!

Leap Year

Thanks for your article on the leap day. I dont remember ever been taught y we had them. Now I know. People sure were smart way back then and they didn't have internet. I'm gonna share this article to the public on the internet ✌!


2-29-72 I have always had fun with it. In non leap years my mom always let me have the 28th and the 1st! I continued it of course because who doesn’t want a two day Birthday? I currently know 3 other leaplings one of them being my husbands best friend. Hope you all have great birthdays tomarow, my celebrations start today!!!!

Leap Year tradition

Neither my youngest daughter nor I are Leapings, but we love Leap Year. We have been creating letters to ourselves over the last three Leap Years. We each write own private letter talking about where we live, what we look like, how old we are, what’s important to us, what we love, what we fear, what makes us happy. We put it away, and get it out the next Leap Year. We’re so looking forward to tomorrow to seeing our last letters & creating new ones. Happy birthday to all the Leapings out there!

Leaplings should be called "Leapers"!

My wife Norma was born February 29, 1940 and is celebrating her "20th birthday leaping to 80 in 2020." In non-leap years we celebrate 2-day birthdays ... the last day of February and the day after the 28th. It's Great!

Great Conversation Starter!

Being a Leap Year Baby (Leaping) has always been a good conversation starter..!! You'll sometimes get the, "I know someone who's a Leap Year Baby..." When I turned 9 leap years, my son also turned 9 yrs old, his football jersey # was 9 - so needless to say that my lucky # is 9..!! Happy 2020 birthday to all of us Leapings..!! I'll be celebrating my 11th Leap Year BDay and looking forward to many more..!!


December 17th born leap years ago 2020

I have a Leapling!

My daughter Olivia was born on 2/29/16 so this is the first year since she was born we get to celebrate on her actual birthday! Up until this year we have celebrated on Feb.28th. We wanted to keep her birthday in the same month because we thought celebrating on March 1st would be confusing for her.

My mom was a leapling

My mom was born on leap year. She celebrated her birthday on February 28th in between leap years. My dad was born on January 29th...my mom was born on February 29th and I was born on November 29th. Different years...same date.

FEB 29


Leap Year Baby

Born in 1952 I will be 17 this year! Used to celebrate at my grandmothers' house if there was no 29th and at home on the 29th. As a retired teacher, I loved explaining leap year ever year to my students. Love being a "leapling!"

Leap Year 1972

I was born on leapyear 1972 in Berlin, VT. If there is no leapyear, I celebrate on Feb. 28th as I was born the last day of February NOT the first day of March. This year I will be celebrating with a large party of friends and family as this is more important to me than turning 50 will be.

leap year

I was born on leap year 1952 at home on my parents farm .

Married in 2004

My husband and I got married in 2004, which was a leap year and have been married 15yrs almost 16yrs!

leap year baby

I was born 2-29-68 and Im so ready.It reallt doesnt matter to me because i celebrate on the 28 th and the 1st if there is no leap year.I plan on going on a trip

Todd Jeffery Tyler. Leapling

I have to say that being a leap year baby kind of sucked growing up as a kid I never knew if I was going to have any presents on my birthday because my mom said hope you don't have a birthday this year so you'll get your presents for Christmas. Therefore when my birthday actually came which would be March 1st I wasn't expecting to get anything and 99.9% of the time I did. However I also feel that being a late bling I don't age as fast as everyone else cuz I am 47 years old and I feel 25 literally please explain this one. Also my mom try to have all three of us boys on a leap year she had my youngest brother on February 27th 1984 which was a leap year she had my middle brother on March 21st of 1976. Why she want to have all three of us on leap year I have no clue however I was the lucky one I guess or was I?

Leap Year is produced by GOD=7_4 Theory

GOD=7_4 is a mathematical model/program/algorithm/initial condition/potential law of physics/'fractal'/alphanumeric code that explains many phenomenons. There are 4 primary lunar phases of roughly 7 days - ~7.4 days - each thus 4 weeks in a 'moonth'. Lunar year + 7 day week + 4 days = 365 day solar year. The lunar month is 29.53 days. If we use 7.4 days x 4 = 29.6 x 12 = 355.2 days + 7 day week + 4 days = 366.2 days.

The Julian Calendar established 7 thirty-one day months + 4 thirty day months + February's 28 (7x4) days. 7/4=July 4th or 7 April 30 AD: Good(7__4) Friday(74) when Jesus(74=J10+E5+S19+U21+S19) was nailed on(74) the Cross(74=C3+R18+O15+S19+S19). Y'shua(74) bar Yosef was born on 17.4.748 AUC / April 17, 6 BC.

Therefore, GOD=7_4 explains the lunar phases, lunar year, solar year, Roman Calendar, and Jesus' birthdate & date of Crucifixion.

Leap year baby

I'm a leap year baby born on 2-29-80 I hate it. Sucks really , does it mean anything???


2 29 72 here. I have always had fun with my birthday. I also take the 28th and the 1st to celebrate. It makes it easier to include more friends and family that way. Happy Birthday to all the other leaplings out there!!!!

A plot point in a Gilbert & Sullivan Operetta

In The Pirates of Penzance, Frederick (the young hero) was supposed to be apprenticed to a pilot, but his nursemaid, who was hard of hearing, mistakenly apprenticed him to a PIRATE. Just when he thinks himself finally free, the Pirate King reappears to inform him that his apprenticeship lasts until his "21st birthday" - but since he was born on February 29, he has to serve them until he is 84! Everything works out in the end, of course - the pirates all turn out to be members of the nobility and are pardoned, and Frederick gets to marry Major General Stanley's daughter. (Sorry about the spoilers, but it's not like the operetta was supposed to be a thriller!)


I am a leap year baby I have never heard of a leapling. There are other great facts here that I never knew. Thank You
Feb. 29 1956

Leap year

I was born Feb 29 1960 so it was fun when I was younger telling everyone that I was really 2 or 3 Then they would ask About March 1 and I would say no I was born In Feb Still to this day I think it funny how many things do not take Feb 29