On PN interview day, kids in the same year can be 8 months apart. Do the maths and give yours a head start.
Hong Kong kindergartens usually hold PN (pre-nursery) interviews around November of the year after a child is born, and every child born in the same calendar year sits in the same cohort. Babies born January to April, known locally as 大B, are about 19–22 months old at interview. Those born May to August (中B) are about 15–18 months, and those born September to December (細B) are only 11–14 months. At that age a few months is a big gap in speech and independence.
This calculator estimates your chance of conceiving in each month you pick, based on both parents’ ages and any health conditions. It then applies an average pregnancy length of 266 days from conception (standard deviation 14 days) to work out the chance your baby is born in each month, and so which group they land in. Monthly conception rates by the woman’s age follow Dunson et al. (2004); the man’s age and health conditions scale that rate.
Results are statistical estimates, not medical advice. Please talk to your doctor about your own situation.