A birthday party needs supplies in six groups: planning and invitations, decorations, tableware and food, hats and activities, gifts, and cleanup. Start two weeks out: set the guest list and theme at 14 days, order supplies at 10 days, confirm RSVPs at 7 days, assemble and test decorations at 3 days, set up the day before, and leave food, ice and any helium latex balloons for party day.
Use the timeline to pace the work, the quantity table to size your order, and the checklists to make sure nothing small gets missed. All quantities are rules of thumb; adjust them for party length and how many adults are staying.
Two-week birthday party timeline
| When | What to do |
|---|---|
| 14 days before | Set the date, time, place and guest list. Pick a color scheme or theme. Send invitations with an RSVP date about a week before the party. |
| 10 days before | Order non-food supplies: hats, balloons, banner, tableware, favor bags, candles. Ordering now leaves time to replace anything that arrives damaged. |
| 7 days before | Chase missing RSVPs and finalize counts. Order or plan the cake. Ask about food allergies. |
| 3 days before | Assemble party hats, thread the banner, test-inflate one balloon, pack favor bags, and wrap the gift. |
| 1 day before | Set up decorations and the table. Inflate air-filled balloons. Charge the camera or phone. Clear space for coats and gifts. |
| Party day | Pick up the cake and ice, fill helium balloons, set out food and drinks, and lay out the emergency kit. |
The 3-day step is the one people skip, and it’s where most last-minute stress comes from. Flat-pack hats, DIY banners and new balloons all hide small surprises, so find them while there’s still time to fix them.
How much to buy: quantities by guest count
These multipliers are common planning rules of thumb for a two-to-three-hour party. Guests lose track of cups and grab extra napkins, so the per-guest numbers run higher than one each.
| Item | Rule of thumb | 10 guests | 20 guests | 30 guests |
|---|---|---|---|---|
| Plates | 2 per guest (meal + cake) | 20 | 40 | 60 |
| Cups | 2 per guest | 20 | 40 | 60 |
| Napkins | 3 per guest | 30 | 60 | 90 |
| Forks and spoons | 1.5 per guest | 15 | 30 | 45 |
| Party hats (all kids) | 1 each + 2 spares, or +15% above 10 | 12 | 23 | 35 |
| Favor bags | 1 per child + 2 | 12 | 22 | 32 |
| Ice for drinks | About 1 lb per guest | 10 lb | 20 lb | 30 lb |
| Large trash bags | 1 per 10 guests + 2 | 3 | 4 | 5 |
For a mixed kids-and-adults party, the hat line needs more thought. How many party hats you need breaks it down by guest type and pack size. If you’d rather enter your numbers and get a list back, the party supply calculator works out hats, balloons, banner length, ribbon and tableware with a buffer included.
The birthday party supplies checklist
Planning and invitations
- Guest list with a contact for each family
- Invitations with date, time, address, end time and RSVP date
- Allergy and dietary notes for guests
- Venue booking or a backup plan for bad weather if outdoors
Decorations
- Banner or garland for the main wall
- Balloons, ribbon, and weights for anything helium-filled
- Tablecloth or table runner
- A photo spot: a backdrop wall, a large balloon, or a banner behind the cake
- Removable adhesive hooks, painter’s tape or other wall-safe fixings
Tableware, food and cake
- Plates, cups, napkins and cutlery (see quantities above)
- Serving spoons, tongs and bowls
- Cake, candles, a lighter, a cake knife and a server
- Drinks, ice and a cooler or bucket
- Labels for dishes containing common allergens
Hats, favors and activities
- Party hats, assembled, plus spares
- A crown or special hat for the birthday child
- Favor bags, filled and closed
- Game supplies and prizes, and a playlist
Gifts
- Your own gift, wrapped
- A table or basket for guests’ gifts
- A pen and list to note who gave what, for thank-you notes
Cleanup and emergency kit
- Trash and recycling bags, paper towels, wet wipes
- Clear tape, scissors, a marker, spare batteries
- Basic first-aid items and any medications guests have mentioned
- Phone charger and a spot to set down the camera
- Bathroom restock: toilet paper, hand towels, soap
Supplies that need prep time
Party hats
Most kids’ party hats ship flat. The Olen kids’ party hats with pom poms, for example, include 9 cones and 2 crowns that you fold, fit with pom poms and thread with elastic. Build them on day 3 and store them upright so the pom poms don’t crush.
Banners
Some banners arrive unstrung. The blue felt pennant banner has 12 felt triangles, each about 5.1 x 6.1 in, that you thread onto an 8.2 ft string with the included plastic needle. Once threaded, the flags slide, so you can bunch them or spread them to fit your wall. Plan the hanging method too; the guide to hanging party banners without damaging walls walks through wall-safe options.
Balloons
Decide early whether balloons will float. The 30 in yellow smiley face birthday balloon has a self-sealing valve and comes with ribbon, but it floats only with helium; filled with air, it works as a wall or backdrop piece. Inflate foil balloons to about 80–90% so the seams aren’t strained. For a full garland or arch, the balloon arch strip guide covers balloons per foot and step-by-step setup.
A practical timing note: helium-filled latex balloons usually float for a much shorter time than foil, so fill latex on party day. Air-filled balloons can go up the day before.
Gift wrap
Wrap the gift at the same time you pack favor bags. A printed roll like the happy birthday ribbon, 15 mm wide and 30 ft long, covers the gift, the favor bags and a few balloon tails in one color scheme. It’s decorative ribbon, so keep it off uncovered food.
Adjust the list for where you’re hosting
At a party venue
Ask what the venue provides before you buy anything. Many supply tables, chairs and sometimes tableware, and many have rules about tape on walls, confetti, open flames or helium balloons. Get those rules in writing a week ahead so your decorations match them.
Outdoors
Wind changes everything. Tie banners to posts or railings with string instead of relying on tape, weigh down tablecloths with clips, and keep balloons and paper hats out of direct sun for long stretches. Add sunscreen, bug spray and extra water to the emergency kit, and have a rain plan.
At school or daycare
Check with the teacher first. Classrooms often limit homemade food, balloons or certain decorations, and they’ll know the exact headcount. Bring hats already assembled and pack everything in one bag that the teacher can hand out.
Adult birthdays
Drop the favor bags and game prizes, and add more drinks, ice and glassware. Hats become optional photo props, so a small basket is usually enough.
Things people forget
These are easy to overlook because they aren’t decorations. Check them off the night before:
- Candles and something to light them
- A knife that can cut the cake cleanly
- Serving utensils for every dish
- Ice, and somewhere to keep it cold
- Enough trash bags to change them mid-party
- Tape and scissors within reach of the decorations
- A charged phone or camera for the cake moment
Safety notes for the setup
Uninflated and popped latex balloons are a choking hazard for young children, and US balloon packaging warns about children under 8. Pick up pieces as soon as a balloon pops and keep unused balloons out of reach. Tie helium balloons to weights so ribbons don’t trail across walkways.
Pom poms, glue dots and small favors are also small parts. Keep them with an adult until they’re attached or handed out, and keep lit candles clear of hats, napkins and hanging decorations.
Frequently asked questions
What supplies do I need for a kids' birthday party?
Cover six groups: invitations, decorations (banner, balloons, table cover), tableware and food (plates, cups, napkins, cake, candles), hats and favors, gift supplies, and a cleanup and emergency kit. The checklist sections above list the items in each.
How far in advance should I buy birthday party supplies?
About 10 days before is a comfortable target for decorations and tableware. It leaves time to replace anything damaged and to assemble hats and banners a few days before the party.
How many plates, cups and napkins do I need per guest?
A common rule of thumb is 2 plates, 2 cups and 3 napkins per guest, since people use separate plates for food and cake and lose track of cups. For 15 guests, that's 30 plates, 30 cups and 45 napkins.
Do I need helium for birthday balloons?
Only if you want them to float. Air-filled balloons are fine for garlands, wall displays and floor decorations, and they can be inflated the day before. Foil balloons labeled as floating with helium will not float on air.
What should go in a party emergency kit?
Clear tape, scissors, a marker, spare batteries, wet wipes, paper towels, extra trash bags, basic first-aid items and a phone charger. Keep it in one bag near the cake table.
When should I set up birthday decorations?
Set up banners, table decorations and air-filled balloons the day before if you have the space. Leave helium latex balloons, food and ice for party day.
