Independent. No sign-up. Nothing leaves your browser.

Puppy calculators that show their working

Most puppy tools divide weight by age, multiply by 52, and call it a prediction. Ours are built on veterinary growth standards modelled from the bodyweight records of millions of young dogs, and every page prints the formula and the study it came from.

See how the maths worksRead the sources

Choose a calculator

Growth and size

How big your puppy will get, and whether it is growing on track.

Feeding and nutrition

How much food, how many calories, and how that changes with age.

Age and life stages

Converting weeks to months, and what to expect at each stage.

Breeding and whelping

Due dates and the whelping timeline, counted from the right event.

Cost

What the first year actually costs.

Why these answers differ from other puppy calculators

Puppy growth is an S-curve, not a straight line. It is slow at first, accelerates, then flattens as the growth plates close. A toy breed is already about a third of its adult weight at eight weeks; a giant breed is barely a tenth of the way there. Any tool that applies one linear formula to both is going to be confidently wrong for at least one of them.

We use size-specific centile curves instead, so the answer accounts for how your puppy's size category actually grows, and we report where your puppy sits on the curve rather than only guessing its final weight. The trajectory is the part your vet cares about. The methodology page explains it in full, including the two places where the method stops being reliable.

Where the reasoning is written out

Every calculator shows its formula, but the arguments behind them live in the guides: how big your puppy will get, how accurate these predictions really are, how much to feed at each age, and what the socialisation window actually costs if you miss it.

What we will not do

We do not publish medication dosing calculators. Getting a dose wrong on a small puppy causes real harm, and the correct number depends on the exact product, current weight and health status. That belongs with your veterinarian. Our disclaimer sets out the full position, including the signs that mean you should stop reading and call a vet.