The Ultimate Guide to Milestone Birthdays: Everything You Need to Know

Welcome to everything you need to know about milestone birthdays!  🥳


We're delighted to share the what, why and other key information to help you celebrate.


Keep reading to find the answers to these common questions or click on the link and jump directly to the answer:

What are the Milestone Birthdays?

Let's start with the numbers you need to know:











Quite simply, these are the milestone birthdays for adults.


Another way to remember which birthdays are considered milestones for adults?


The age the person turns will always end in zero…with the exception of the 21st birthday. The origins of 21 being an important age trace back to medieval times. A boy could become a page at age 7, a squire at age 14 and a knight at 21 years of age.

In the United States, celebrating a 21st birthday means you are officially an adult!  Among the privileges that come with turning 21:

  • Legally drink alcohol in all 50 states
  • Purchase/use marijuana in states where it is legal
  • Enter the floor of all casinos
  • Make travel reservations more easily in some cases*

Once upon a time, rental car companies required drivers to be 25 years old. Their logic was that a 25-year old would be a more experienced driver. Today, the minimum age for car rental varies by company.

*Since most travel-related companies have their own policies, please check with them to see if there's any age requirement or additional fee for being under age 25. A valid ID is (almost always) required upon check-in and you don't want any unpleasant surprises.


21st birthday milestone

 The 21st is the only adult milestone birthday that doesn't end in a '0.'


Why is Turning 50 a Big Deal?

Aside from the 21st birthday, the most popular birthday for adults to celebrate is their 50th.  It’s the half point of a century, which conveys far greater importance than saying you’ve been alive for 40% of a century.

Another reason the 50th birthday is widely celebrated is because someone turning 50 is more likely to:

  • Be in good health
  • Be experienced enough to reflect upon their accomplishments so far
  • Have children who are old enough to not need constant tending
  • Have parents who are young enough to not need constant tending  😉

Someone celebrating their 50th birthday is also celebrating being:

  • 600 months old 
  • 2,608 weeks old
  • 18,262 days old 
  • 438,000 hours old
  • 26,280,000 minutes old  

When you look at those numbers, turning 50 is a piece of cake!  By all means, kick up your heels and dance!  🥳


50th party decor

 Want THE easiest party decoration ever?!
Check out this 50th birthday banner and stand.
In under 2 minutes, you'll have an elegant centerpiece...AND it's reusable!

Great birthday ideas for someone turning 50 include a party, a trip or birthday getaway or even a group gift.

The 50th birthday is seen to be “golden” and adding black conveys a sense of elegance. You can’t go wrong with party decorations in black and gold, whether you’re looking to celebrate in a ballroom or at an intimate dinner with family and friends.

50th birthday card black gold decorations

Why are they called Milestone Birthdays?

The ancient Romans are to thank for the very first milestones.  

As part of building the first system of roadways, they wanted to standardize and communicate the distance traveled between two points. They erected stone obelisks on the side of the roads every mile and called them “millestones”, because 1,000 paces equaled one mile and “mille” means 1,000 in Latin.

Milestone birthdays traces back to this example of a Roman milestone

Roman milestone XXIX on Via Romana XVIII
Photo credit:  Julio Reis

Lest you think this a piece of history better left to the past, the next time you’re driving along a highway in the US, check the side of the road.  You’ll find milestones, more commonly called mileposts, every mile, though today they're nearly always made of metal.

Over time, the word milestone morphed from distance traveled to the passage of time (milestone birthdays) or the achievement of an important event (such as graduating from high school or college, getting married or buying your first home). 


Why Do We Celebrate Milestone Birthdays?

Milestone birthdays are technically no different than any other birthday.  By definition, your birthday celebrates the day you were born and you turn another year older every 365 days from then.

From a practical standpoint though, milestone birthdays, from the ages of 30 upwards, only come along once every 10 years.  Perhaps that’s why we refer these as “big” birthdays, as in, “Sooooo, when do you hit the big 3-0?”


Do milestone birthdays reflect the prior decade coming to a close or do they represent the welcoming of a new decade? Likely both!  


7 Top Reasons to Celebrate Milestone Birthdays

Personally, I'm a fan of ALL birthdays, not just the ones that end in zero. 🥳

But there are at least seven great reasons to commemorate milestone birthdays above all others, including:

  1. They represent a new beginning and time for reflection
  2. People understand these are “big” birthdays
  3. We remember our own milestone birthdays above others
  4. They honor aging with celebration
  5. They show we care and set a positive example for our kids
  6. Party goods and greeting cards reflect their importance
  7. Plenty of birthday slogans for turning 21, 30, 40, 50, 60, 70, 80, 90 

 Keep reading as each idea is discussed below!

 Happy 50th birthday party
This 50th birthday centerpiece for table is easy and elegant! Learn more here and be ready to celebrate the big day.

Milestone Birthdays Represent a New Beginning and a Time for Reflection

Ever stopped to think about the tradition of blowing out birthday candles?

Inevitably, someone will say, “Make a wish!”

 Lit candles on a 50th birthday cake

It turns out that this tradition and its ability to improve our lives is grounded in science.


Researchers at The Wharton School  studied the phenomenon of New Year’s resolutions. As many of us can attest, the new year is a time for setting goals, losing weight and exercising more.


The team found that “temporal landmarks” (basically, the imaginary lines we draw in our minds to delineate the passage of time, such as the start of a new week, month or year) can be very motivational because they provide an opportunity for reflection and encourage people to look at their lives overall.


Applying this to birthdays, the 48-year old version of you may not have exercised, but your 49th birthday might just be the motivation you need to start running every week. 


Who knows?  As you approach your 50th birthday you may realize that this is the decade you compete in half marathons.


People Understand Milestone Birthdays are “Big” Birthdays

Collectively, we understand that milestone birthdays are most important.  


We make greater efforts for those birthdays, from cards to gifts to celebrations and trips.


If you miss a 46th birthday party, you can make a promise to attend the 47th one. 

Miss a 50th birthday party? 


You have to wait another decade until the person has another “significant” birthday! 

Anecdotally, I’ve seen much higher RSVPs for milestone birthday parties than non-milestone birthdays and the replies usually note the person’s age, “I'd love to celebrate Peggy's 80th birthday with her!

80th milestone birthday for her woman and daughter celebrating

 This lovely lady is Peggy. Though it's hard to believe, she really was turning 80!  Her daughter helped her celebrated with decor from Birthday Butler.

We Remember Milestone Birthdays More than Others 

Milestone birthdays are usually the ones we remember the best. 

Ask someone how they celebrated their 21st birthday and you’ll likely get a story.  Inquire about how they celebrated turning 20 or 22 and a blank stare is far more common.


The same can be said about turning 30, 40, 50, 60, 70, 80, 90 or 100 years old vs. the adjacent years. The milestone birthdays are the ones we put in our mental scrapbooks.


In their book, The Power of Moments, authors Chip and Dan Heath discuss the characteristics of things we remember most.

They’ve found we are more likely to remember moments or events that occur during times of transition such as going from one decade to the next. We also tend to prioritize “peak” events in our memory bank.

A 50th birthday party creates a memorable moment

Milestone Birthdays Honor Aging with Celebration

In a culture that prizes youth, aging is often marked by the loss of things we value (smooth, firm skin; eyes that can see tiny print) and the onset of unwelcome conditions (grey hair, aching joints).

Milestone birthdays are one of the few times when we can CELEBRATE aging.

Events like a birthday party give guests a chance to toast the guest of honor and reminisce about shared stories.

Man celebrating milestone 90th birthday

 Karl is still going strong at 90.  May we all enjoy great health into our golden years!

Remembering Milestone Birthdays Shows We Care and Sets a Good Example for the Kids

Giving gifts or celebrating with parties and gatherings are a fun, and admittedly a much easier way of saying,
“I’m really glad you’re alive.  I’m happy you’re been in my life for another year.”

As most kids view their own birthdays as happy events to look forward to, milestone birthday celebrations of the adults in their lives sets a positive example.


It's also worth mentioning that from a sociological perspective, birthdays serve as important rituals to help indoctrinate the youngest members into society. Nearly every culture in the world celebrates birthdays!

Party Goods and Greeting Cards Reflect the Importance of Milestone Birthdays

You can tell a lot about which birthdays are most important just by checking out greeting cards, invitations and party goods. 

Milestone birthdays usually have several options with the person’s age emblazoned on the front of the card or invitation—“Happy 40th Birthday!” or “As You Turn 50…”   Meanwhile, non-milestone birthdays have to make do with “for any age” cards.

Similarly, party goods for a 60th birthday are plentiful, while you’d be hard-pressed to find napkins, let alone decorations, for a 59th birthday or a 61st birthday.  

(Milestone party goods and greeting cards have many options for 30th, 40th, 50th, 60th, 70th, 80th and 90th birthdays.  The ages used above were to show examples.)

Milestone Birthday Slogans Abound

Milestone birthdays are the ones that make it into pop culture and sometimes even on party decorations. 

From “50 is the new 40” to “Life begins at 50”, there are a wide range of popular phrases and slogans, including:

  • “Flirty thirty!”
  • “Lordy, lordy!  Look who’s 40!”
  • “50 and fabulous” and “Fifty is nifty”
  • “Sixty and sassy”
  • “Seventy and sensational”
  • “Eighty and awesome”

Note that these slogans also work well for the theme of a birthday party!

More Milestone Birthdays

Whether you are celebrating you're 30th birthday or 90th birthday, the old saying is most definitely true: aging is MUCH better than the alternative!


Now you know about milestones...but what about birthstones?  Please check out this blog post to learn more.

Need milestone birthday ideas? 
Click here to read our post dedicated to 50th birthday ideas.