The overall Which? test score is made up of the following star ratings, all determined by our rigorous lab tests.
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 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.