What to write in an 18th birthday card

Turning 18 is an exciting time of life that a few of us here at thortful can just about remember. All of a sudden, you’re legally old enough to take out a mortgage, get married, vote in elections, and perhaps most importantly, buy alcohol.

It’s also when you’re considered to be a fully grown adult, which is why writing an 18th birthday message for a friend or loved one is often different from the cards you gave them in previous years. But if that’s the case, then how do you know what to write in an 18th birthday card?

Since this is a very special occasion that only happens once (unlike all those other boring birthdays that slide by without any extra fanfare), we’ve put together some 18th birthday card messages for you to take inspiration from or just outright steal if you like (we promise we don’t mind).

Heartfelt 18th birthday card wishes

The level of heartfeltness (yes, apparently that’s a real word) which you add to the card is totally up to you. If you’re looking for something quick and sweet to include in a cute 18th birthday card, try one of these:

  • Congratulations on becoming a kind, funny and truly wonderful adult. 
  • Wishing you all the happiness in the world on your 18th birthday.
  • You’ve already done so much in your life; let’s see what adulthood will bring!
  • Happy 18th birthday to the most amazing person who ever existed.
  • We’re so proud to have watched you transform from the cutest kid into the most beautiful adult. 

The messages above work nicely for an 18th birthday card message, but you might want to really melt their heart, in which case, make it more personal by including details of their childhood.

If you’re their parent, you could tell them that their arrival in this world was the most magical day imaginable and share a memory. You could also include a mini flashback to their favourite toy as a child or something that you used to do together when they were small – feel free to be as sappy as you like on this very special occasion.

Funny messages for an 18th birthday 

You can’t beat having a good old giggle, especially on someone’s birthday. To help you get the birthday boy or girl chuckling their socks off, we have a wide range of funny 18th birthday cards. Here are some messages you could use inside:

  • You’re now a mature and responsible adult. Can I borrow a tenner?
  • We don’t mean to rush you, but isn’t it time you found your own place?
  • You have officially reached adulthood. Each birthday from now on will make you feel that little bit older. Welcome to the club.
  • See those tiny wrinkles next to your eyes? Prepare to start building an impressive collection.
  • Now that you’re 18, make sure to drink responsibly. That means not forgetting to buy everyone a round.

Perfect quotes for an 18th birthday card

Becoming an adult when you turn 18 is a major turning point in life. It’s when many young people start truly thinking about jobs they’d fancy doing for a living, what kind of things they want to achieve, and the kind of person they will grow into over the coming years. 

This is the perfect opportunity to offer them motivation and fuel their can-do attitude by including an inspirational 18th birthday message in their card. Below are a few suggestions of quotes by famous people, and a quick Google will present countless more.

  • “The purpose of our lives is to be happy.” – Dalai Lama
  • “Many of life’s failures are people who did not realise how close they were to success when they gave up.” – Thomas Edison
  • “You only live once, but if you do it right, once is enough.” – Mae West
  • “The whole secret of a successful life is to find out what is one’s destiny to do and then do it.” – Henry Ford
  • “Do all the good you can, for all the people you can, in all the ways you can, as long as you can.” – Hillary Clinton
  • “Live for each second without hesitation.” – Elton John

18th birthday card messages for your son

Writing a card for your son can be difficult, as you may not want to come across as too schmaltzy, but at the same time, you need him to know just how much he means to you. This is also a milestone birthday that separates adolescence from manhood, so you’ll want to strike the right balance.

What you write in your son’s 18th birthday card is, of course, entirely up to you, but here are a few ideas that may help.

  • Happy birthday, son. Not a day goes by that we don’t feel proud of who are and what you do for others around you. 
  • Our tiny bundle of joy is now a tall, hairy man who leaves the toilet seat up. Despite the smelly socks, we love you more each day!
  • Whenever you’re having a hard time or doubting yourself, all you have to do is talk to us, and we’ll remind you how caring, resilient and incredible you really are.
  • Our baby boy is now an intelligent, creative and capable young man. We couldn’t be more proud of you if we tried.
  • No matter what you do in life, we’ll always be here to cheer you on, offer support and help you in any way we can. We love you so much and wish you the happiest 18th birthday in history.

18th birthday wishes for your daughter

If it’s your daughter’s 18th birthday, you can get a bit soppier with your 18th birthday card messages. Here are a few more suggestions for an 18th birthday card greeting message she’ll never forget.

  • Here’s to our fabulous daughter on her 18th birthday. May the bubbles flow freely and the dancefloor never empty!
  • On this very special day, we just want you to know that we will always love you with all our hearts and never stop being here for you. 
  • Our darling daughter is now a beautiful young woman. Wishing you all the happiness in the world on your special day. 
  • You may be an adult but you’ll always be our little girl. However, we’re still not getting you a pony.
  • We’re so proud of the strong, independent young woman you’ve become. Now, get out there and smash the patriarchy!

Hopefully, you’ve now got plenty of inspiration for what to write in an 18th birthday card that they’ll treasure. Of course, these are just suggestions, and when it comes to 18th birthday greetings messages, you can always go your own way for something entirely unique.

Mind you, even the best-written 18th birthday message in the world won’t matter without a suitable card. Here are a few of our favourites:

Whether you’re looking for a card that’s funny, cute, classic, or traditional, and no matter what your relation to the recipient, check out our wide range of 18th birthday cards. And don’t forget that they’re now allowed to celebrate with a cheeky tipple, so why not send them fizz and a cardwine and a card or beer and a card?