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Dog Blood Volume Calculator

Calculate total circulating blood volume and haemorrhage thresholds for fluid therapy planning and surgical preparation.

🩺 Dog Blood Volume Calculator
Enter your dog's details below to get an instant result.
Total Blood Volume
-ml
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10% loss threshold
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30% loss (Class III)
Warning: For use by or under supervision of qualified veterinary professionals only.

What Is the Dog Blood Volume Calculator?

Calculate total circulating blood volume and haemorrhage thresholds for fluid therapy planning and surgical preparation.

Essential for fluid therapy planning, transfusion dosing, and haemorrhage assessment. Calculate total blood volume and key loss thresholds instantly.

Every result is based on published veterinary research and breed-size-specific growth data — not generic averages. This tool is completely free, works instantly in your browser, and requires no account or sign-up.

How to Use This Calculator

1
Enter Your Dog's Details

Fill in the required fields above — typically your dog's weight, age, or breed size. Every field has a clear label and hint.

2
Click Calculate

Press the calculate button to get your instant result. No page reload, no account needed, no waiting.

3
Review Your Result

Your result appears immediately below the calculator. It includes the primary answer plus additional context where relevant.

4
Use the Information

Share, print, or save your result. Always discuss health-related results with your veterinarian before making decisions.

How It Works

Total blood volume in dogs is approximately 85 ml/kg bodyweight. This value is used in transfusion calculations, to estimate maximum safe blood donation volumes (15-20% of TBV), and to classify haemorrhage severity. Class I haemorrhage (under 15%) is compensated. Class II (15-30%) begins to cause tachycardia. Class III (30-40%) causes hypotension. Class IV (over 40%) is immediately life-threatening.

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Veterinary Research

Every formula is derived from peer-reviewed veterinary studies and clinical guidelines, not guesswork or generic rules.

Instant Results

No page reload, no waiting, no account needed. Enter your details and your result appears immediately.

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100% Private

All calculations happen in your browser. Nothing you enter is ever stored on our servers or shared with anyone.

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Always Free

Every calculator on Doggy Calculators is and will always be completely free to use — no premium tier, no catch.

Frequently Asked Questions

What is the total blood volume of a dog?+
Approximately 85 ml/kg, compared to 66 ml/kg for cats and 70 ml/kg for humans.
How much blood can a dog donate safely?+
15-20% of total blood volume — approximately 400ml from a 25kg donor dog.
At what blood loss does a dog need a transfusion?+
Class III haemorrhage (30%+ blood loss) with haemodynamic instability, or any patient with PCV below 20% and ongoing anaemia.
What is the difference between whole blood and pRBC?+
Whole blood contains all components. pRBC (packed red blood cells) have plasma removed and are used when volume is a concern. Fresh whole blood also provides clotting factors.
How does blood volume affect drug dosing?+
In hypovolaemic patients, drug distribution is altered. Injectable anaesthetic agents in particular should be dosed conservatively in haemorrhaging patients.

Sources & References

This calculator's formulas are based on the following peer-reviewed and authoritative veterinary sources:

⚠️ These calculators are reference tools only. Always consult a licensed veterinarian before administering medication or making medical decisions.