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Category 09 of 12 · Animal pregnancy

Biology Calculators

Biology calculators help pet owners and farmers plan around animal life cycles: due dates for dogs, cats and cows, when a dog's next heat is likely, a cat's age in human years and how big a puppy may grow.

They give estimates based on typical gestation lengths and growth patterns. Always confirm pregnancy and health questions with a veterinarian.

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01Pregnancy and breeding

Due dates and heat cycles. · 4 live

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Dog Pregnancy Calculator

Find your dog’s due date from the mating date (63 days, normal range 58–68).

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Cat Pregnancy Calculator

Enter the mating date to estimate when your cat will give birth, plus the normal birth window.

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Cow Gestation Calculator

Enter the breeding or AI date to estimate your cow's calving date and window.

02Age and growth

Human-year ages and adult size. · 2 live

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Cat Age Calculator

Convert your cat's age to human years with the vet-recognised chart.

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Dog Size Calculator

Estimate your puppy's adult weight from its age, current weight and expected size class.

Quick guide

Which calculator do I need?

Match what you’re trying to do with the right tool.

If you’re…Expecting puppies
UseDog Pregnancy Calculator
If you’re…Expecting kittens
UseCat Pregnancy Calculator
If you’re…Planning calving
UseCow Gestation Calculator
If you’re…Tracking a female dog's cycle
UseDog Heat Cycle Calculator
If you’re…How old is my cat in human years?
UseCat Age Calculator
If you’re…How big will my puppy get?
UseDog Size Calculator

How we build and check these calculators

Every calculator on Tuff Search shows the formula or method it uses, a worked example and its limits, and lists its sources where facts matter. Health, money and legal-rule pages are checked against official or peer-reviewed sources and dated. Read how we build and review calculators in our Editorial Policy.

FAQ

Frequently asked questions

Short answers about the biology calculators.

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We add new calculators regularly. Email suggestions@tuffsearch.com with the calculation you need.

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Dogs about 63 days from ovulation (roughly 58–68 days from mating); cats about 63–67 days.

No. They give typical estimates. A vet can confirm pregnancy, due dates and health.

Mating date and ovulation are not always the same day, and breed and litter size affect gestation, so calculators show a window rather than one date.

It is a rough guide that improves as the puppy gets older and when the parents' weights are known.

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