How we compare to other labour probability calculators
There are several labour probability calculators online. Here's how ours compares.
Up-to-date data (2023-24)
Most calculators use older studies. We use the latest NHS Maternity Statistics (2023-24) and CDC Natality Data (2023), giving you predictions based on current birth patterns.
More accurate statistical model
We use a Johnson SU distribution that properly captures the heavy left tail of preterm births. This means more accurate predictions for early deliveries, matching ONS preterm breakdown data.
More personalisation options
We're the only calculator that adjusts for fetal sex, BMI, twins/multiples, and interpregnancy interval. These factors can shift your expected date by several days, making your prediction more personalised.