Marks & SpencerLittle Smiles

How we test absorption rate

We apply synthetic urine to the nappy and time how long it takes to fully absorb the fluid. We repeat this four times to measure the rate of absorption as the nappy fills up.

How we test protection against leakage

We apply synthetic urine to the nappy and record the amount of liquid that leaks out of the nappy. We repeat this four times to record leakage as the nappy fills up.

How we test holding wetness inside

We place filter paper on top of a fully fluid-loaded nappy and weigh it down. We measure the amount of liquid absorbed by the filter paper to work out how well the nappy holds in fluid.

How we test breathability

This rating is based on scores from our panel of parent testers.

How we test parents rating

The parent ratings for nappies tested before September 2023 are based on a survey of 674 UK parents in June 2022. The parent ratings for nappies tested after this date are based on a user panel of 30 babies who try out the nappy and whose parents give their thoughts on it.