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Dog heat cycle calculator

By VicayaGlobal Calculator Editorial Team

17 September 2026 approximate next startSee full result

Estimate the next heat date from the first day of the last heat and your dog’s usual start-to-start interval. This canine heat cycle calculator projects calendar dates only. It cannot identify fertile days, prevent pregnancy or decide when to breed.

Dog

The first observed signs, such as swelling or discharge; not the end of bleeding.

Use your dog’s recorded interval. The default200 days is an illustration, not an inferred breed rule.

17 September 2026 approximate next start

A calendar projection from your interval, not a biological guarantee. Watch actual signs and confirm concerns with your vet.

Projected cycle1
17 September 2026; assumes the same interval each time
Projected cycle2
5 April 2027; assumes the same interval each time
Projected cycle3
22 October 2027; assumes the same interval each time

What this means

F-PETS-HEAT-001: projected start=last start+n×entered interval days for n=1,2,3, using UTC calendar days. No calendar-month conversion, breed multiplier or fertile-window formula is applied.

VCA describes wide variation between dogs, with intervals around 4–12 months and an average near 7 months. That population context does not give a precise prediction for your dog. Irregular early cycles, missed signs and health changes can make a calendar estimate unreliable.

Use actual records and a veterinary consultation for reproductive decisions. Calendar dates are not contraception; do not assume a day outside a predicted window is infertile.

Only your browser processes the dates. A copied scenario keeps selected values in the link fragment.

When to see a vet

Formula and sources

Sources reviewed 19 October 2026. Each names the figure it supports.

This page is an educational estimate, not veterinary advice.

Frequently asked questions

How does a dog heat cycle calculator predict the next heat date?

It adds your dog’s usual start-to-start interval to the first day of the last heat. This tool uses the interval you enter and labels all future dates approximate.

Can a canine heat cycle calculator show fertile days?

Calendar arithmetic cannot reliably identify ovulation or infertile days. This tool deliberately gives no fertility window; consult your vet for reproductive testing and decisions.

What if I do not know my dog’s interval?

The default is an example only. Keep records of actual starts and ask your vet about unexpected or irregular patterns; do not treat a population average as your dog’s known interval.

Does bleeding stopping mean pregnancy cannot occur?

No. Do not rely on the end of visible bleeding or a calendar prediction to prevent pregnancy. Ask your vet about appropriate prevention.

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