What to Write In a 21st Birthday Messages - 69 Different Ideas

Turning 21 is a big birthday! It’s one we take very seriously in western cultures, as after an 18th birthday, it’s the next birthday that signifies your arrival to adulthood. When we turn 18, most age restrictions don’t apply to us, but still a few. At 21 the world is your oyster!

Any big birthday, and especially a 21st birthday, deserves a gift and most importantly a birthday greeting card. However, knowing what to write on a 21st birthday isn’t always that easy.

Even a short 21st birthday message needs a bit of consideration. How close are you to the recipient, and what is your relationship with them? Can they see the humour in your card and can they take a joke, or should you stick to being friendly and celebrative? Do they like heartwarming messages, or do they prefer to keep it light?

Luckily for you, we have curated some of the best messages to write in a 21st Birthday card to take all the pressure off your shoulders.

Funny Things To Write In A 21st Birthday Card

Most 21 year olds will take a joke, and most likely won’t be insulted with a card being humorous about their age. Funny birthday card messages would be perfect from siblings and friends - we can leave the gushing heartwarming messages for the parents and grandparents! Choose one of our funny 21st birthday wishes below, and personalise it where you see fit. Perhaps use some personal details that you and the recipient share, for example a trip that you both went on, or how you both met all those many years ago.

1. Enjoy turning 21 today - it’s all downhill from now on!
2. By 21, Jane Austen had written Pride and Prejudice. But you’re still doing great!
3. By 21, Steve Jobs had founded Apple. But you’re still doing great!
4. You’re 21! You are officially an adult… and old.
5. 21 years of being a muppet.
6. 21 looks good on you.
7. Look out world, here you come!
8. 21 today! Time to get your sh*t together.
9. Happy 21st Birthday! Drink responsibly… don’t spill any of it.
10. Time to get drunk and forget you’re getting old. Happy 21st!
11. Time to grow up! Happy Birthday.
12. Happy 21st Birthday! Don’t grow up… it’s a trap!
13. Here’s your annual reminder of how thoughtful I am - Happy 21st Birthday!

Heartwarming Things To Write In A 21st Birthday Card

Perhaps humour isn’t the way to go, but instead a heartfelt and thoughtful message will work. You could use this opportunity to wish them a happy 21st birthday, and let them know how proud you are of them and what they mean to you. This is officially their entrance into adulthood, and that means a lot!

1. Have a wonderful day today on your 21st Birthday.
2. How time flies - Happy 21st Birthday.
3. So proud of who you have become over these 21 years.
4. You are such a beautiful person, inside and out. Happy 21st!
5. 21 - This is big! So proud of you and all you have accomplished so far.
6. So proud of what you have achieved and what you are going to achieve. Happy 21st birthday!
7. Life isn’t about finding yourself - it’s about creating yourself. Happy birthday!
8. Can’t quite believe you are 21! I remember you running around in nappies.
9. 21 and amazing.

Happy 21st Birthday Message for Daughter

Your daughter is turning 21. This is the perfect opportunity to wish them a happy birthday, and explain how proud you are of them and why. This greeting card you send may well become a keepsake card for them, that they will treasure for a number of years after this birthday. Choosing a beautifully designed card and well thought out personal message is a must!

1. We are so proud of you - Happy 21st Birthday daughter.
2. To the most amazing daughter we could have wished for - Happy 21st Birthday!
3. I can’t wait to see what your future holds for you!
4. So proud of the woman you have become.
5. No matter what, you’ll always be our little girl.
6. You’ll always be our princess!
7. You make us so proud, each and every single day.
8. I know that the path ahead for you is bright – you deserve every success
9. You know I’ll always be here for you son, cheering you on, with a shoulder to cry on.
10. I can’t believe the little baby girl I held in my arms is turning 21 today.

Happy 21st Birthday Message for Son

So your son is finally turning 21, and where has that time gone! Choosing the perfect message for their birthday card is a great way to let them know how proud you are of who they have become over these 21 years. 

1. We are so proud of you - Happy 21st Birthday Son.
2. To the most amazing son we could have wished for - Happy 21st Birthday!
3. I can’t wait to see what your future holds for you!
4. So proud of the man you have become.
5. No matter what, you’ll always be our little boy.
6. You’ll always be our prince charming!
7. You make us so proud, each and every single day.
8. I know that the path ahead for you is bright – you deserve every success
9. You know I’ll always be here for you son, cheering you on, with a listening ear, and doing your ironing.
10. I can’t believe the little baby boy I held in my arms is turning 21 today.

Happy 21st Birthday Message for Sister

1. Happy 21st Birthday Sister - Forever looking up to you!

2. Happy 21st Birthday Little Sister. I still remember when we used to dress up!

3. I’m so lucky to have a sister like you.

4. Forever my partner in crime.

5. So lucky to have a sister and a best friend in one.

Happy 21st Birthday Message for Brother

1. Happy 21st Birthday Brother - Forever looking up to you!

2. Happy 21st Birthday Little Brother. I still remember when we used to wrestle!

3. I’m so lucky to have a brother like you.

4. Forever my partner in crime.

5. Bro - I can’t believe you’re 21! Happy Birthday.

Inspirational 21st Birthday Message

Using a more inspirational message is always appropriate when you are truly proud and impressed by the recipient, and what they have achieved or overcome in their time. It might be that the recipient has had a tough time up until their 21st birthday, but yet they have persevered and overcome their challenges. It may be that the recipient has achieved a great deal in a relatively short amount of time - this could be related to starting their own business, buying their own home, striving to help others through charitable work etc. 

1. I’ve always looked up to you and I’m so proud of the person you have become. It’s a blessing to have you in my life.
2. On your 21st birthday, you deserve all of the happiness and joy that life can bring.
3. You have always inspired me. With all you’ve been through so far, you persevere and move forward. Stronger than ever on your 21st birthday.
4. All you’ve accomplished in your 21 brief years on this earth - it’s astounding!
5. You have accomplished so much in such little time! What a role model you are for those that know you. I’m so proud of the grown-up you have become.
6. What does life have in store for you? An adulthood filled with joy, happiness and success is my birthday wish for you.
7. You’ve so many choices left to make as you turn the corner past 21. Whatever path you take, may it provide all of the happiness and success that you deserve.
8. What an impressive person you have become.
9. Go now, and do amazing things!

21st Birthday Quotes

Sometimes you can say all you need to say with a quote. Below we have compiled a list of quotes that can be applied to reaching that 21st birthday milestone. Of course, you could always accompany a message along with one of these 21st birthday quotes.

1. “Always remember – you are braver than you believe, stronger than you seem, smarter than you think, and more loved than you know.” – Christopher Robin, Pooh’s Grand Adventure
2. “All the world is a birthday cake, so take a piece, but not too much.” George Harrison
3. “21, if truth be told, is partly young and partly old.” Unknown
4. “Birthdays are good for you, the more you have the longer you’ll live.” Unknown
5. “Don’t just count your years, make your years count.” – George Meredith
6. “Whatever with the past has gone, the best is always yet to come.” – Lucy Larcom:
7. “Today you are you! That is truer than true! There is no one alive who is you-er than you!” – Doctor Seuss
8. “Youth is happy because it has the ability to see beauty. Anyone who keeps the ability to see beauty never grows old.” – Franz Kafka

Hopefully the above 21st birthday best wishes have inspired you in some way. Choosing any of the above messages should be a great place to start from in writing the perfect 21st birthday card. The one tip we could give is to personalise the message to a memory or connection you have with the recipient. This will make it a truly personal and unique message that they are sure to love and treasure. If you are stuck on finding the perfect 21st birthday card, then please take a look at our collection of birthday greeting cards. There are a number of designs to choose from.