What is the difference between pocket, all-in-one and birth-to-potty reusable nappies?

What is a pocket reusable nappy?

A pocket nappy is a waterproof outer shell, usually polyurethane laminate (PUL) with a soft fleece or suedecloth lining, and an opening at the back or front that forms a sleeve. You push an absorbent insert into the sleeve, and the whole thing goes on the baby in one piece like a disposable. At change time the insert comes out (or falls out in the wash) and both parts are washed.

The point of the design is separation. Because the absorbent part and the waterproof part dry separately, a pocket nappy dries faster than a nappy where they are sewn together. Because the insert is loose, you can swap it: a thin microfibre insert for a two-hour daytime change, a bamboo or hemp insert (or two) for a long car journey or the night. The UK Nappy Network's glossary describes pockets as a compromise between the ease of an all-in-one and the quicker drying of nappies with inserts, which is a fair summary.

The cost of that flexibility is the stuffing. Every clean nappy has to be reassembled before it can be used, which most families do in a batch in front of the television. Shell-only pocket nappies from UK makers were listed at £9.99 to £18.00 each on the day we checked, with inserts sold separately or included.

What is an all-in-one reusable nappy?

An all-in-one (AIO) has the absorbent core sewn into the waterproof shell. Nothing to stuff, nothing to fold, nothing to lose in the machine. It is the design closest to a disposable and the one that nurseries, grandparents and reluctant partners take to fastest.

Two trade-offs follow from sewing everything together. First, drying: a thick core attached to a PUL shell cannot be spread out, so all-in-ones are the slowest type to dry indoors. Makers try to help with tongue-style cores that flap out, and some newer designs (Little Love Bum's QuickDry, for example) are built specifically around this problem. Second, wear: the waterproof layer is washed every single time the nappy is used, so Edinburgh Council's reusable nappy guide notes it wears out faster than a separate wrap that is only washed when soiled.

You also cannot easily boost an all-in-one. Some have a pocket as well (a hybrid), but for a heavy wetter you are usually laying a booster on top of the core rather than inside the nappy, which changes the fit. Prices on the day we checked ran from about £11.50 per nappy in a ten-pack (Bambino Mio Miosolo) to £17 to £21 for a single premium all-in-one.

A close relative is the all-in-two (AI2, sometimes snap-in-one): the absorbent pad poppers onto the shell instead of being sewn in. If the shell is only damp you can un-popper the wet pad, snap in a dry one and reuse the shell, which makes a small kit go further.

What does birth-to-potty mean, and is it a type of nappy?

It is not a type. Birth-to-potty (BTP), one-size (OS) and one-size-fits-most all mean the same thing: a nappy whose rise and waist adjust with rows of poppers so that one nappy is meant to fit from the early weeks to potty training. Pocket nappies, all-in-ones, all-in-twos and fitted nappies all come in birth-to-potty versions, and most of them also come in sized versions (newborn, size 1, size 2).

The catch is in the word 'birth'. The UK Nappy Network's glossary is blunt: most one-size nappies will not fit a newborn very well for the first four to eight weeks, even if the baby falls inside the stated weight range, because newborns are slimmer than older babies of the same weight. Edinburgh Council's guide makes the same point from the other end, warning that the fit may be compromised at the lowest and highest ends of the range. A birth-to-potty nappy on a 3 kg baby tends to gape at the legs and sit high on the chest; on a tall two-year-old the rise runs out.

• Sized nappies (a two-part system with size 1 and size 2, or newborn plus birth-to-potty) fit better at both ends and are gentler on a newborn's umbilical stump, but you buy two sets, so the total outlay is higher.
• Birth-to-potty only is the cheapest route if you can tolerate a slightly poor fit for the first month or two, or if you bridge that period with disposables, a hired newborn kit or a council trial pack.
• Newborn hire kit then birth-to-potty is the middle path many nappy libraries and retailers now sell (see the low-cost kit guide linked below).

How do the types compare on drying time, absorbency, fit and price?

The table brings the designs together, including the two older systems (fitted nappies with a wrap, and flat terries or prefolds with a wrap) because they are still the cheapest way to fill a nappy bucket and most councils' guides describe them. Prices are what UK brand and retailer sites displayed on the day we checked; they move with sales and are given as a range, not a quote.

On cost alone, the question 'are pockets cheaper than all-in-ones over time?' has a fairly consistent answer: a pocket shell that outlives two babies and gets a second set of inserts is cheaper per change than an all-in-one whose sewn-in core has thinned and whose PUL has been washed a thousand times. But the difference between the two modern designs is small next to the gap between either of them and flats with wraps, which cost roughly half as much per change and dry in a fraction of the time.

Why do reusable nappies leak, and does the type matter?

Leaks are the reason most people give up, and almost all of them trace back to one of five causes. Only the last two are about the nappy itself.

1. Fit at the legs. The leg elastic should sit in the knicker line, tucked into the crease at the top of the thigh, with no gap and no fabric poking out from under a wrap. Warwickshire County Council's guide puts it simply: any nappy showing outside the cover will wick moisture onto clothes. Birth-to-potty nappies on small newborns leak here most.
2. Not enough absorbency for the gap between changes. A single microfibre insert is a two-hour daytime insert. Nights, long naps and car journeys need bamboo or hemp, or a second layer. Warwickshire's guide notes that once a baby sleeps through, a washable booster is usually needed.
3. Compression. Microfibre in particular gives back liquid when squeezed, which is what a car-seat harness, a sling or a tight vest does. Natural fibres hold on to more under pressure. Pocket nappies are easiest to fix because you can change what is inside.
4. Detergent build-up or fabric conditioner. The NHS nappy-changing guide says not to use fabric conditioner on cloth nappies because it makes them less absorbent. The Nappy Network wash guide adds that repeated over-dosing of detergent builds a film that causes leaks and smells; the test is bubbles in the final rinse.
5. Worn PUL or elastic. Waterproof laminate delaminates (looks bubbled or crackled) and elastic goes slack, especially on all-in-ones that are washed every use, on nappies dried on radiators or in direct sun, and on nappies that have been soaked. Clean Cloth Nappies' routine is explicit that soaking degrades elastics prematurely.

If a nappy leaks the moment you switch brands of washing powder, or every nappy in the kit starts leaking in the same week, the cause is almost always the wash routine rather than the nappy. Fix the routine before buying more nappies.

How many reusable nappies do I need to wash every two days?

Work from changes per day, not from a kit size on a website. The NHS says young babies may need changing as many as 10 or 12 times a day, and older babies around six to eight. Add a day's worth for the nappies that are in the wash or still drying, and you have your number.

The numbers explain why type and kit size are linked. If you own slow-drying all-in-ones and live in a flat with no outdoor line, you either buy more nappies or wash more often. If you own pockets or flats, twenty is usually enough. That is the practical case for mixing: a core of fast-drying pockets or flats for daytime, plus three or four fitted nappies or boosted pockets for nights, plus a handful of all-in-ones for the nursery bag.

Which type should I buy for a first kit?

Nobody can tell you which shape suits your baby's thighs, so the honest advice from councils and nappy libraries alike is to try several before buying twenty of one. That is what trial packs, library hire kits and the retailers' three-nappy 'try me' bundles (Bambino Mio's was £50 on the day we checked, Little Lamb's Discovery Bundle £63 on sale) are for. Several councils sell or lend trial packs for £5 or nothing; the council schemes guide linked below lists the ones we could verify.

In shortIn short: pocket and all-in-one are designs, birth-to-potty is a size. Pockets dry fastest and are easiest to boost; all-in-ones are the quickest to put on and the slowest to dry; sized nappies fit newborns better but cost more overall; flats and wraps remain the cheapest per change. For a first kit, borrow or buy a mixed trial before committing, and remember that most leaks are about fit and washing, not the label.