Veterinary Dose Volume Calculator
from the label dose to millilitres.
Turn the dose on a product label (mg per kg) into the volume to draw up (mL), and see how many intramuscular sites to split it across. There is no drug list: the numbers always come from your product label.
Dose Volume
Volume (mL) = body weight (kg) × dose (mg/kg) ÷ strength (mg/mL)
Volume to give
From mg/kg to millilitres
Two numbers from the label and one from the animal.
Multiply the body weight by the dose to get the total amount of drug in milligrams, then divide by the product strength to get the volume. Example: a 450 kg cow, a label dose of 7.5 mg/kg and a 100 mg/mL product: 450 × 7.5 = 3,375 mg, and 3,375 ÷ 100 = 33.75 mL.
Beef Quality Assurance guidance limits each intramuscular injection site to about 10 mL. Larger volumes are split evenly across several sites, at least a hand's width apart, in the neck muscle.
How to use this calculator
- Choose kg or lb at the top of the calculator, then enter the animal's body weight. Weigh it if you can; a weight tape or the animal weight calculator is the next best option.
- Enter the dose from the product label in mg per kg. If the label gives mg per lb, multiply it by 2.2 first.
- Enter the product strength in mg per mL, also from the label. If it is given as a percentage, 1% is 10 mg/mL.
- Pick the route the label or your vet tells you to use. Only intramuscular (IM) doses are split across injection sites.
- Check the volume against the label, and print the result if someone else will give the injection.
Reading the result
Total volume is the amount to draw up for one dose; the line under it shows the total milligrams of drug. For IM injections, injection sites tells you how many sites to use so that no site gets more than 10 mL, and how much goes in each. For subcutaneous, intravenous and oral doses it shows one administration. If the answer is far from what you expect, check the strength first: mixing up a 10% and a 20% product halves or doubles the volume.
Common questions
Why does weight matter so much?
Under-dosing can make treatment fail and help resistance build up; over-dosing can harm the animal and lengthen withdrawal. A weight estimate from a tape can be 5–10% off, so weigh the animal when the dose margin is small.
Why is there no drug list?
Products with the same drug come in different strengths, and doses differ between countries and species. Copying the numbers from the label in your hand avoids using the wrong product's dose.
Why does the calculator split only intramuscular doses?
It applies the Beef Quality Assurance limit of 10 mL per IM site, because a large volume in one muscle causes more tissue damage and blemishes in the meat. The same guidance prefers subcutaneous injection when the label allows either route. For subcutaneous doses, follow any per-site limit on the label.
My label gives the dose in mL, not mg/kg. What do I do?
Then the label already gives you a volume: multiply it by the animal's weight in the units the label uses (per kg, per 10 kg, per 50 kg and so on). If the label also gives the mg/kg dose and the mg/mL strength, enter them here as a cross-check.
Decision support only. Not a substitute for your veterinarian.