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Dog Dehydration Calculator

Calculate fluid deficit and replacement rate for dehydrated canine patients based on clinical dehydration percentage and bodyweight.

💧 Dog Dehydration Calculator
Enter your dog's details below to get an instant result.
Fluid Deficit
-ml
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Replacement rate
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Total with maintenance
Warning: Dehydration percentage is a clinical estimate. Fluid plans should be reassessed every 2-4 hours. Add maintenance rate to replacement rate for total fluid administration.

What Is the Dog Dehydration Calculator?

Calculate fluid deficit and replacement rate for dehydrated canine patients based on clinical dehydration percentage and bodyweight.

Estimate the fluid deficit and calculate replacement fluid rate for a dehydrated dog based on clinical dehydration percentage and patient weight.

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

Fluid deficit is calculated as: body weight (kg) x dehydration percentage / 100 x 1000 = deficit in ml. This deficit is replaced over a chosen period (4-8 hours) on top of the maintenance fluid rate (2-3 ml/kg/hr). Clinical dehydration percentage is estimated from physical signs: 5% shows subtle changes, 8% shows prolonged skin tent and dry mucous membranes, 10% shows severe signs, 12% 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

How do I assess dehydration percentage in dogs?+
5%: subtle, tacky mucous membranes only. 8%: prolonged skin tent (over 2 seconds), dry MM, slightly sunken eyes. 10%: severe skin tent, very sunken eyes, weak pulse. 12%: collapse, shock.
How quickly should I replace the fluid deficit?+
Mild-moderate dehydration over 6-12 hours. Severe dehydration may need faster replacement of 50% in 4 hours then reassessment. Avoid overcorrection.
Should I add electrolytes?+
For prolonged dehydration, check electrolytes. Hartmann's (Lactated Ringer's) is a balanced crystalloid suitable for most cases. Add potassium supplementation if hypokalaemic.
How do I know the plan is working?+
Improving skin turgor, moist mucous membranes, improving pulse quality, increasing urine output (target 1-2 ml/kg/hr), and improving mentation.
When should I switch from IV to oral fluids?+
When the patient is able to drink and absorb fluids normally without vomiting — typically when 50-70% of the deficit has been replaced and the animal is stable.

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.