Diaper calculator

How the calculator works

The short answer: a baby uses about 3,000 diapers in the first year. The tool walks through the year one day at a time, adds that day's expected count, and assigns it to the size your baby is likely to be in. Then it adds it all up by size.

The daily counts come from published charts:

• 0 to 1 month: 8 to 12 a day
• 2 to 4 months: 8 to 10 a day
• 5 to 8 months: 7 to 9 a day
• 9 to 12 months: 6 to 8 a day
• 13 months and up: 5 to 7 a day

The figures through 12 months are from Pampers' chart of diapers by age. Pampers sells diapers, so we checked it against Healthline's medically reviewed guide, which gives 8 to 12 a day for newborn size, down to 5 to 7 for size 4. The toddler row comes from that guide. The NHS expects 10 to 12 changes a day at the start and 6 to 8 once a baby is older, which fits the same curve. The headline uses the middle of each range. The low and high figures use the ends.

How long each size lasts comes from the months-per-size figures on the Pampers chart: 1.6 months in newborn, 1.7 in size 1, 2.8 in size 2 and 5.8 in size 3. The weights shown are Healthline's. Box counts through size 3 are also Healthline's. For size 4 and up we assume 120 per box, so enter your own number if you have one.

Default prices come from published ranges: ThePricer lists about $0.15 to $0.25 for store brands, $0.20 to $0.35 for name brands and $0.35 to $0.50 or more for premium, as of October 2026. Healthline gives $0.25 to $0.30. We use $0.20, $0.28 and $0.42. Prices change by store and by size, so replace them with what you see on the shelf.

A worked example

Take a baby at birth, in name-brand diapers at $0.28 each.

• Newborn: about 7 weeks at 10 a day is 490 diapers, or 4 boxes.
• Size 1: about 7 weeks at 9.2 a day is 480 diapers, or 3 boxes.
• Size 2: about 12 weeks at 8.6 a day is 732 diapers, or 6 boxes.
• Size 3: about 26 weeks at 7.5 a day is 1,341 diapers, or 10 boxes.

That comes to 3,043 diapers, $852 for the year and about $71 a month. Healthline's estimate of about $1,000 in the first year includes other supplies, so the two are in the same range. For a registry, the tool suggests 15 boxes. That leaves room for your baby to grow at their own pace.

Edge cases

A bigger baby. Some babies skip most of the newborn size. Tick the box and the tool cuts newborn to about two weeks, so that row falls from 490 diapers to 160, and moves the rest to size 1.

An older baby. Enter an age and the tool plans the next 12 months from there, skipping sizes the baby has already outgrown.

Daycare. Many centers ask you to supply diapers, so the count stays the same, but some will go to daycare. Ask about their brand and quantity rules.

Cloth diapers. This tool covers disposables. Healthline suggests at least 20 newborn cloth diapers, washing 12 to 18 at a time.

A count is not a health check

This number is for shopping. The AAP suggests changing every three to four hours, or whenever a diaper is soiled, to help prevent rashes. It also lists fewer than six wet diapers a day as a possible sign of dehydration in infants. Call your pediatrician if you are worried.

Why a fund can beat boxes

Boxes are hard to get right before you meet the baby. A diaper fund lets guests help with the cost while you buy the right size at the right time. On RegistryBee you can list diapers from any store and receive the money instead. See what else to list on the baby registry checklist.