How to choose diapers: a guide for the first days, weeks and months

How many diapers you'll actually use (and why it matters)

In the first year you'll change a diaper, on average, 6 or 7 times a day. That works out to roughly 2,500 diapers. The first three months are the heaviest — up to 10–12 a day — and then frequency drops.

Knowing this helps with two things. First, it explains why diapers are by far the most constant expense of the first year (more than milk, more than clothes). Second, it stops you from buying too many before the birth: it's one of the most common and most expensive mistakes.

Sizes: how they work, when to skip ahead

Diaper sizes go by weight, not by age, and the numbers are roughly standard across brands:

Size 0 / Micro (1.5–2.5 kg) — preemies or very small newborns only. Most babies skip it.
Size 1 / Newborn (2–5 kg) — first days and first two or three weeks.
Size 2 (3–6 kg) — roughly from one month to six weeks.
Size 3 (4–9 kg) — the «workhorse» size, you'll use it longer than any other, roughly from 3 to 9–10 months.
Size 4 (7–18 kg, ranges vary) — usually from 9–10 months on.
Size 5 and above — older toddlers, until potty training.

Operating rule: change size when the diaper leaves red marks on the thighs, when it fills up too quickly, or when it starts to leak. The weight printed on the package is a guide, not a rule.

What to buy before the birth (not much)

The classic mistake is showing up to the hospital with three giant boxes of size 1. What happens: the baby is born at 4.2 kg, in three weeks they're already 5.5 kg, and you're left with 150 size-1 diapers to give away. Or the opposite: born at 2.7 kg, stays in size 1 for six weeks, and your three boxes aren't enough.

What to do instead: just one pack of size 1, plus one pack of size 2 in the house as a buffer. Everything else, you buy as you go — Amazon and supermarkets deliver the next day anyway.

For the very first days there are mixed «first days» packs that contain both size 1 and size 2 in the same box — designed precisely for this problem. A solid starter is the Pampers First Days mixed pack (size 1 + 2, 84 diapers): it costs more per diaper than a regular pack, but it eliminates the risk of guessing wrong and has very strong reviews on softness during the first days.

The first weeks: the baby's skin picks the brand, not you

This is the thing nobody tells you clearly enough: the right brand isn't decided by reading reviews, it's discovered on the baby's skin. Some babies never get a rash from supermarket-brand diapers; others react to the most expensive ones on the market. It's not predictable in advance.

The strategy that works: start with an established brand — Pampers, Lillydoo, Huggies — and watch for 10–15 days. If skin stays smooth and the bottom doesn't get irritated, you're fine. If you see persistent redness that doesn't go away with barrier cream, try changing brand before you start blaming other causes.

For especially sensitive skin or families with a history of dermatitis, the «hypoallergenic, no fragrance, no lotions» category makes sense from day one. A well-reviewed example is Lillydoo size 3 (monthly box, 176 pieces): no fragrances, no lotions, OEKO-TEX certified. Costs about 30% more than equivalent Pampers Baby-Dry, but reduces irritation for reactive skin.

From 3 months on: the size-3 era and the «stock up» choice

When you hit size 3 everything changes. The baby uses fewer per day (5–6), weighs more, and you've figured out which brand they tolerate. This is the moment for big purchases: mega-packs of 150–200 diapers cost 25–35% less per diaper than small packs.

For the mainstream «daytime, high absorbency, fair price» category the long-time benchmark is Pampers Baby-Dry Maxi size 4 (208 pieces): the «workhorse» diaper that works for most babies, has tens of thousands of positive reviews, and in mega-pack format costs less than 0.20€ per piece.

The budget question: is saving money worth it?

Amazon-brand diapers (Mama Bear, now rebranded «by Amazon») cost about 30–40% less than Pampers at the same size. The question is: does the quality hold up?

The honest answer: for most babies, yes — but not for all of them. If you've found that your baby isn't particularly sensitive, trying a pack of Mama Bear Ultra Dry size 4 (168 pieces) is a 25-euro experiment that, if it works, saves you several hundred euros over the year. Reviews are mostly very positive on absorbency, slightly less so on softness compared to Pampers.

Practical strategy: keep a trusted brand for nighttime (where leaks are the real problem) and a cheaper brand for daytime. Most families end up here — even if they don't say so.

Nighttime: do you need a special «night» diaper?

«Night» or «overnight» diapers aren't marketing fluff — they really do contain more absorbent material and last more hours. But if your regular diaper holds 10–11 hours without leaking, you don't need them. Worth trying only if:

– you're finding wet pyjamas regularly,
– the baby happily sleeps 11–12 hours straight,
– you're in the 6 months–2 years range, where night leaks are most common.

Often it's enough to go up one size for nighttime only (size 4 by day, size 5 at night): cheaper and works just as well.

Eco or conventional? The slightly inconvenient truth

Biodegradable or «eco» diapers (corn-based, wood pulp, sugarcane) have a smaller environmental footprint — especially on the fossil-plastic side — but they are not actually home-compostable. They still end up in landfill or incineration, because they hold so much liquid that home composting can't handle them.

That said, for those making an informed environmental choice, brands like Eco by Naty size 2 (132 pieces) are the most serious on the market: 60% biodegradable, plant-based materials, FSC and Nordic Swan certified. They cost about 50% more than Pampers Baby-Dry — that's the ethical-choice premium.

If environmental impact really concerns you, the most effective option is the one nobody wants to hear: cloth diapers. They have a high upfront cost (250–400€) and then are essentially free. The logistics are demanding — especially if you don't have an in-home washing machine. It's your call, and it has to be assessed against your real life, not the ideal one.

My 5-point compass

1. Buy little before birth. One pack of size 1, optionally a first-days mixed pack.

2. In the first 15 days, watch the skin. If it reacts, change brand before changing creams.

3. Once you've found the right brand, switch to mega-packs. You save 25–35%.

4. Run two brands: a premium one for nighttime, a cheaper one for the day. It's the most efficient combination.

5. Don't buy a year of diapers in one go. Sizes change faster than you think and you'll end up with unusable stock.

Recap of products mentioned

Below are the concrete brands referenced in the article, each with a strong review-to-price ratio on Amazon. Five diapers for five different scenarios — not a competitive «top 5»:

🍼 Pampers First Days mixed pack — first days (size 1 + 2)
🌿 Lillydoo size 3 — sensitive skin, hypoallergenic
🐎 Pampers Baby-Dry Maxi size 4 — the mainstream workhorse
💶 Mama Bear Ultra Dry size 4 — Amazon-brand budget option
🌱 Eco by Naty size 2 — the most credible eco choice

And if none of these convince you, that's fine. The «right» diaper is the one that works on your baby's skin, fits your budget, and doesn't make you anxious every time the pack runs out. Everything else is marketing.