Is a size 1 nappy cheaper per change than a bigger size at Tesco, Asda or Aldi?

Why is shelf pence the wrong number on its own?

Size 1 tickets often print the lowest £/each in the bay. That is one change. A newborn week has more changes than a toddler week. Which? says babies use six to 12 disposable nappies a day in the first few months, then fewer. The money question is unit price × changes, not which bag looks cheapest on the edge ticket.

1. 1
   Copy £/each for size 1 Use the shop’s printed unit price, or pack price ÷ count if the ticket omitted £/each.
2. 2
   Copy this week’s change count Use the number of changes you are actually doing, or the NHS / Which? ranges below if you are planning. Do not pick a low count to make the sum look cheaper.
3. 3
   Multiply by 7 Weekly cost = pence each × changes per day × 7.
4. 4
   Repeat for the next size you will actually wear A size 4 at 6p with eight changes can cost more or less by the week than a size 1 at 3p with twelve changes. That is the comparison — not 3p versus 6p on the shelf.

How often does the NHS say to change a nappy?

NHS “How to change your baby's nappy” says babies need frequent changes, and the nappy should be changed as soon as they wet or poo, otherwise the skin becomes sore and red. It gives a planning range: young babies may need changing as many as 10 or 12 times a day; older babies around 6 to 8. NHS Best Start in Life uses the same 10 to 12, then 6 to 8, and notes you may change as many as 4,500 nappies before potty training.

NHS nappy rash lists “change wet or dirty nappies as soon as possible” and “not cleaning the nappy area or changing the nappy often enough” among the causes. That is the official reason this page does not treat “fewer changes” as a saving.

Official NHS wording is to change as soon as the nappy is wet or soiled. Extra absorbency on a plus or night pack is not a substitute for that. This is not medical advice; a rash that does not settle is a pharmacist or GP question.

What does size 1 versus a bigger size look like by the week?

Use published tickets for the pence, and NHS / Which? ranges for the changes. Aldi’s size 1 page on 10 September 2026 listed a 24-pack at £0.75 / 3p each. Tesco Fred & Flo size 4 jumbo was 6p. Which? own-brand size 4 sat near 6p in 2023–24. Tesco’s Pampers New Baby size 1 Essential 50-pack listed £8 / 16p, or £5.50 Clubcard / 11p.

The point of the table is the method. Size 1 at 3p can still be a cheap week if you keep NHS-style changes. Size 1 at 16p with 12 changes is a dear week even though it is still “size 1”. A bigger size only enters the sum when the baby has moved into that band.

Where do Tesco, Asda and Aldi size 1 tickets sit?

Aldi’s live size 1 listing is the clearest official £/each in this set: 3p. Which?’s Aldi versus Lidl table also put Aldi size 1 at 3p (then a 28-pack). Tesco lists a Fred & Flo Newborn Size 1 50-pack; the UK groceries page did not return a stable £ price to the fetch used here — divide that week’s pack price by 50. Asda Little Angels newborn packs were not fetched live; use the Asda £/each on the size 1 bag.

• Do not mix a size 1 24-pack with a size 4 jumbo and call the jumbo “more expensive per change” for a newborn.
• Do not use a first-year lump sum from a budget tool as a substitute for unit price × this week’s changes.
• If Express only has a branded Essential pack, that size 1 pence can sit far above Aldi 3p — still multiply by 10–12, not by one.

Can I wear a size 1 longer to make the pence look better?

No — not as a money method. NHS nappy-rash guidance is to change wet or dirty nappies as soon as possible and to leave nappies off when you can. Which? also says regular changes matter because babies have sensitive skin. A “saving” that comes from fewer changes is not a unit-price win on this page.

Buy the size that fits the weight range on the pack. Which?’s size guide puts size 1 at about 2–5kg. Holding a baby in size 1 to keep the 3p ticket is a fit question, not a pence question.

In short, is size 1 cheaper per change?

In shortSize 1 often prints the lowest pence — Aldi’s 10 September 2026 ticket was 3p. Per change that can still be cheap. Per week it depends on 10–12 NHS-style changes, not the shelf digit. A bigger size is a different week, once the baby is in that band. Do not cut changes to save pence.