40th birthday ideas: party themes and surprises

Here are ten ways to mark a 40th, from a big party to a quiet day. Keep the two or three that sound most like the guest of honor.

1. A themed party: a cocktail night, a decade throwback, art deco, or black and gold.
2. A dinner with close friends, in a private room or with a private chef at home.
3. A surprise party, run by a partner, sibling or close friend.
4. Two or three nights away with their closest friends, at a cabin, a beach town or a city they love.
5. An outing: a tasting, a cooking class, a concert, a festival or an amusement park.
6. A casino night or a murder mystery dinner at home.
7. A milestone story night, where friends each tell one memory.
8. A photo timeline from childhood to 40, hung where everyone can see it.
9. An at-home spa day or a staycation in their own city.
10. A family celebration: a backyard BBQ or a long Sunday brunch.

A party suits someone who loves a crowd. A dinner, a trip or an outing suits someone who would rather talk than mingle. Compare the seven formats below before you spend anything.

Not sure? Ask the guest of honor: "Do you want the spotlight, or just your people?" The spotlight points to a party. Their people point to a dinner or a trip.

A good 40th birthday party theme is one the guest of honor would pick for themselves. Carry it through the invitation, the food and the music. Each of the 12 themes below has a 40th design to start from.

Every design in the table is in the 40th birthday invitations collection linked at the end of this guide. Design free, pay when you send — from $9.99.

Plan a surprise 40th in eight steps: check they want one, add an insider, lock the invitation and time the arrival. The InviteBird settings below keep the secret off any screen the birthday star might see.

1. Ask the person closest to them if they would enjoy a surprise. If the answer is "maybe," plan a party they know about. Keep one surprise inside it, such as a friend who flies in.
2. Add your insider as a co-host. InviteBird lets you add up to five co-hosts on every plan. Each uses their own account, and you share the guest list and messages.
3. Turn on a password before you send. Only people you give it to can open the invitation. The invitation email tells guests it is private and to ask you for the password.
4. Switch on "Only guests on my list can RSVP." Even if the link and password get passed around, only your guests can reply.
5. Set up the games before you send. Keep Guess the birthday star and Wishes & memories on. Switch off Who knows the birthday star best: adults answer that quiz themselves, so it would spoil the secret.
6. Schedule the invitation for a time the birthday star is busy, such as a workday morning. You pick the date and time, pay once at checkout, and it sends itself.
7. Give guests an arrival-by time well before the guest of honor walks in. Your insider runs the decoy plan, such as "a quiet dinner for two."
8. Name one point of contact. You or a co-host answer guest questions in the shared inbox. Nobody texts the birthday star by mistake.

The password and the guest-list switch are included with every event. For the reveal and late guests, see the surprise section of the birthday party checklist linked below.

The activities that work at a 40th are about the guest of honor's life, not about getting older. Choose two or three, then leave plenty of time to talk.

Match the food to the format: courses for a dinner, stations for a party, and one standout cake for either. Give every signature drink a no-alcohol twin in the same glass.

• A private chef dinner or family-style courses for a group under 20.
• Food stations for a bigger party: tacos, sliders, pasta or a grazing board.
• A dessert table with the cake in the middle.
• A cake: two number-shaped cakes, the theme colors, or their childhood bakery's classic.
• A late-night snack, such as pizza or fries, if the party runs past 10 p.m.

Put each twin on the same tray as the drink it copies, so nobody has to ask. The Emily Post Institute notes that you don't need an alcoholic drink to give or join a toast. If the bar is open, plan rides home before the party starts.

Decorate with one palette from the invitation, number balloons, simple table settings and a photo wall of the decades. Those few pieces do more than a room full of party-store extras.

1. Choose nine photos: one at birth and one every five years up to 40.
2. Hang them left to right on a string or a board, with the year under each photo.
3. Build a teen-years playlist. Open Billboard's year-end Hot 100 for each year from age 13 to 18, and pick the songs they would know.
4. Set out one object from each decade under the wall, such as a toy, a jersey or a concert ticket.

A decor kit in your palette saves time: look for balloons, a banner and table pieces.

The right idea depends on what the person enjoys, not on whether they are a husband, a wife or a friend. Find the row that sounds like them and start there.

Send 40th birthday invitations for a home party three weeks out, or four if your friends have busy calendars. When guests need flights or hotels, send them at least six weeks ahead, eight if possible. Make the RSVP deadline about eight days ahead, which leaves time to chase late answers and confirm the food.

Emily Post's timing chart gives cocktail parties a week to a month and formal dinners a three-to-six-week window. A big occasion or a crowded guest list, the chart adds, calls for sending sooner. If the party is a surprise, the invitation should say it near the top.

For complete invitations, including surprise and dinner versions, see the adult birthday invitation wording guide linked below.

This example follows one host through the eight surprise steps, from the first question to the keepsake. Change the names, the theme and the dates to fit your plan.

Cut anything that turns the guest of honor into the punchline. A 40th lands well when it celebrates who they are now.