What this page does
Litter weight gain uses two weights and a day count, same arithmetic as puppy growth rate.
From the mating date the page adds 58, 63, and 68 days. The due estimator walks the remaining time toward 9 weeks. Weaning bands are milk, gruel, weaning, then solid food, as topics, not orders.
Worked example: 0.8 kg to 1.2 kg in 7 days is 0.4 kg in a week.
How the estimate works
Press Calculate for the date window or the cost split. A breed can set the size on the puppy-age count. It does not predict a whelping hour, and it does not change the 58, 63, and 68 day counts.
A mating date is not proof of pregnancy. A week count is only as good as the date you remember.
The midpoint is not the whelping day. Dogs can be early or late and still be within a normal talk with a clinic.
Limits
Litter cost divides your numbers by the puppy count. It is not a price list.
The mating example of 1 August 2026 is the default story on this cluster. Your date replaces it only after you calculate.
Why a window instead of one date?
Questions
Because gestation clusters around 63 days and still spreads. Publishing one day would look more precise than the biology is.