Guess low and you're hunting for a store at 10 p.m. Guess high and half your suitcase is diapers. Here's a simple rule that scales with your child and your trip.
Step 1: Start with a per-day number by age
Little ones use fewer diapers as they grow, so plan by age band, not one fixed number. Typical starting points:
| Age | Diapers per day |
|---|---|
| Newborn (0–1 month) | 10 |
| 1–4 months | 9 |
| 5–8 months | 8 |
| 9–12 months | 7 |
| 1–2 years | 6 |
| 2–3 years | 4 |
Your child may use more or fewer than this. If you know your own number, use it.
Step 2: Multiply by the days of your trip.
Step 3: Add travel time.
Add about one diaper per hour of travel, for each direction.
Step 4: Add a delay day in the carry-on.
Keep one extra day's worth with you in case of a cancelled flight or a long traffic jam.
Step 5: Add a small spare.
About 10% extra covers blowouts and bad days.
Worked example: an 18-month-old on a 5-day trip with 8 hours of travel each way. 6 per day × 5 days = 30, plus 16 for travel, plus 6 for a delay day, plus 3 spare = about 55 diapers. About 14 of those go in the carry-on (8 for the flight plus the delay day).
Don't forget the extras
- Overnight diapers: one per night from about 9 months.
- Swim diapers: about two per swim day, for the pool, beach or water park.
- Wipes: around 2–3 wipes per change adds up fast. In the example above, that's roughly 120 wipes.
- Diaper cream and a small changing mat.
Should you just buy diapers there?
Often, yes. Unless you're going somewhere remote or on a cruise ship, it's usually easier to pack a couple of days' worth plus your travel and delay supply, then buy the rest when you arrive. You'll free up a lot of suitcase space.
Potty training?
Decide whether your child is in pull-ups or trained but needs backup. For flights, pull-ups are usually less stressful than underwear.
Coming soon
Let the app do the math
Packworthy's diaper and infant supplies calculator uses this rule. Enter your child's age, trip days, travel hours and swim days, and choose whether you'll buy at your destination. You'll get diapers to pack, diapers to buy, the carry-on count, overnights, swim diapers and wipes, all added to your family list.