Nappy Sizes Explained: A No-Stress Guide for UK Parents
Nappy boxes are labelled by size number, but babies come in weights — and the overlap between sizes confuses everyone. Here's the whole system in one table, plus the signs it's time to size up.
The size table (Pampers Swaddlers)
| Size | Weight (lbs) | Weight (kg) | Typical age |
|---|---|---|---|
| 1 | 8–14 | 3.6–6.3 | newborn–3 months |
| 2 | 10–22 | 4.5–10 | 2–6 months |
| 3 | 13–26 | 6–12 | 5–10 months |
| 4 | 15–34 | 7–15 | 9–18 months |
| 5 | 20–37 | 9–17 | 12–24 months |
| 6 | 30+ | 13+ | 18 months+ |
| 7 | 26–50 | 12–23 | toddler |
| 8 | 30+ | 14+ | older toddler |
Weights overlap on purpose — fit matters more than the number. When in doubt between two sizes, the bigger one usually means fewer leaks.
Four signs it's time to size up
- Red marks around the legs or waist when you change them.
- The tabs barely reach the middle, or you're fastening them at the very edge.
- Frequent leaks — especially overnight. A too-small nappy simply runs out of absorbing capacity.
- The nappy sits low: the waistband should reach just under the belly button.
How many do you actually use?
Plan for roughly 10–12 nappies a day for a newborn, easing to 6–8 by six months and 4–6 past the first birthday. That's why the big multi-packs (100+ counts) work out so much cheaper per change — a newborn goes through a 76-count box in about a week.
Stock-up strategy that saves money
Don't over-buy Size 1 — many babies wear it for only a few weeks. Buy one box of the current size and one of the next size up. Sensitive skin? Fragrance-free, hypoallergenic lines (like Swaddlers) are the safest default for newborns.
See our Baby & Kids range — every box ships free across the UK, and unopened boxes return free for 30 days if you sized wrong.
Pampers Swaddlers sizes we stock
The table above uses Pampers Swaddlers, and these are the boxes we currently stock, with the weight range printed on each pack shown in kilograms.
- Pampers Swaddlers Size 1, 198 count: 3.6 to 6.3 kg, fragrance-free.
- Pampers Swaddlers Size 2, 186 count: 4.5 to 10 kg, fragrance-free.
- Pampers Swaddlers Size 3, 168 count: 5.9 to 11.8 kg, fragrance-free.
- Pampers Swaddlers Size 4, 150 count: 6.8 to 15.4 kg, fragrance-free.
- Pampers Swaddlers Size 5, 132 count: 9.1 to 16.8 kg, fragrance-free.
See more in our Pampers range. Every order ships free across the UK, with free 30-day returns.
