Free tool
Veterinary dose calculator by weight
Enter the animal's weight, the dose rate from the label and the strength of the preparation you hold. The calculator gives the volume to draw up in ml and the total dose in mg.
For veterinarians, as a reference only. This calculator does arithmetic. It does not know the species, breed, age, organ function or the product you hold. Dose rates and the table below are reference defaults that a qualified veterinarian must validate against the product label and the patient. Calculations never replace a vet's judgement, and each clinic sets its own protocols.
ml = weight × dose ÷ strength. Rounded to one decimal; measure to what your syringe allows. For tablets, enter the tablet strength in mg as "strength" and read the result as number of tablets.
Worked example
Bruno, a 28.4 kg Labrador, needs meloxicam at 0.1 mg/kg from a 1.5 mg/ml oral suspension. 28.4 × 0.1 = 2.84 mg. 2.84 ÷ 1.5 = 1.9 ml.
Inside Pet Clinic Software this happens on the chart: the vet picks the drug from the clinic's own drug master (strength, default rate and maximum mg/kg set by your vet), enters today's weight and the rate, and the result is checked before it is logged to the dose log and, for drugs you flag as controlled, the register with vet and witness.
Common small-animal drugs: typical mg/kg ranges
Reference defaults only, to be validated by a qualified veterinarian against the label. These are typical published ranges for dogs unless stated, for orientation while you use the calculator. Species, route, formulation, age, kidney and liver function and the manufacturer's label all change the dose. Cats in particular differ for NSAIDs, paracetamol (never) and some antibiotics.
| Drug | Class | Typical range | Route | Notes |
|---|---|---|---|---|
| Meloxicam (dog) | NSAID | 0.1–0.2 mg/kg | PO / SC | Loading 0.2, then 0.1 daily; not in cats long term |
| Carprofen (dog) | NSAID | 2–4 mg/kg | PO / SC | Once daily or divided |
| Amoxicillin-clavulanate | Antibiotic | 12.5–25 mg/kg | PO | Twice daily |
| Cefalexin | Antibiotic | 15–30 mg/kg | PO | Twice daily |
| Enrofloxacin (dog) | Antibiotic | 5–10 mg/kg | PO / SC | Once daily; avoid in growing dogs |
| Metronidazole | Antibiotic | 10–15 mg/kg | PO | Twice daily |
| Doxycycline | Antibiotic | 5–10 mg/kg | PO | Once or twice daily; give with food |
| Ivermectin (dog) | Antiparasitic | 0.2 mg/kg | SC / PO | Not in MDR1 breeds such as Collies |
| Praziquantel | Dewormer | 5 mg/kg | PO | Tapeworm |
| Fenbendazole | Dewormer | 50 mg/kg | PO | Daily for 3 days |
| Maropitant | Antiemetic | 1 mg/kg | SC | Once daily, up to 5 days |
| Ondansetron | Antiemetic | 0.5–1 mg/kg | PO / IV | Every 12 hours |
| Chlorpheniramine (dog) | Antihistamine | 0.4 mg/kg | PO | Twice daily |
| Furosemide | Diuretic | 1–4 mg/kg | PO / IV | As needed, monitor hydration |
| Ketamine (induction, dog) | Anaesthetic · Schedule X | 5–10 mg/kg | IM / IV | With a sedative; register entry required |
| Xylazine (dog) | Sedative | 0.5–1 mg/kg | IM | Lower in cats; reversible with yohimbine |
| Atropine | Anticholinergic | 0.02–0.04 mg/kg | SC / IM / IV | Pre-anaesthetic |
Ranges compiled from commonly used veterinary formularies for orientation only. This page is not a prescribing guide and does not replace the product label, a formulary or your clinical judgement. Ketamine is a Schedule X drug in India; see the controlled-drug register guide.
Why weight-based dosing goes wrong on paper
Three things cause most dosing errors in a busy clinic: the weight on the card is from the last visit and the dog has gained three kilos; the vial in the drawer is a different strength from the one the dose was memorised for; and the arithmetic is done in the head while the owner is talking. A calculator fixes the third. Software that reads today's weight and the stock strength fixes all three.
Pet Clinic Software's dose calculator sits on the Dose log tab of every patient and on the whiteboard card for in-patients. It converts mg/kg × weight into ml or tablets of the strength in your drug master and writes the dose to the chart in mg and ml. Stock is deducted when the item is billed. For drugs you flag as controlled it adds a register line with the vet, witness and running balance. The hospital whiteboard (Hospital module) shows the next check time on each card.
What safety checks run before a dose is logged?
Inside the app, every dose goes through these checks before it reaches the chart. Hard errors stop the log; warnings need the vet to write an override reason, which is saved with the dose and in the audit trail.
| Check | What happens | Status |
|---|---|---|
| Concentration on file | No strength in the drug master stops the log | Live |
| Drug units | Warns when the strength unit (mg or ml) cannot be converted to ml or tablets, and when a preparation is in IU/ml so the rate is read as IU/kg | Live |
| Maximum dose per kg | Warns when the rate is above the maximum mg/kg your vet set, or when no maximum is set | Live |
| Weight age | Warns when the weight used was recorded more than 30 days ago, or is more than 20 % off the last record (kg vs lb) | Live |
| Allergy flags | Warns when the pet has an Allergy alert or note, and names the drug if the note mentions it | Live |
| Manual verification | The vet must tick "I have checked the drug, concentration, weight and dose" before logging | Live |
| Witness for controlled drugs | Drugs flagged as controlled need a witness name | Live |
| Species-specific limits and drug interactions | Per-species maximums and interaction checks | Planned |
If a check cannot run (for example no weight on record), the app warns rather than guessing. The checks reduce common errors; they do not replace the vet's judgement.
Related: puppy and kitten vaccination schedule · all Pet Clinic Software features · veterinary practice management software for India.
Frequently asked questions
How does the dose calculator work?
Multiply the dose rate in mg/kg by the animal's weight in kg to get the total dose in mg, then divide by the concentration of the preparation in mg/ml to get the volume in ml. For a 28.4 kg dog on 0.1 mg/kg meloxicam from a 1.5 mg/ml suspension: 2.84 mg, which is 1.9 ml.
Are the drug ranges in the table safe to use directly?
No. The table is a reference default, not a prescribing guide, and must be validated by a qualified veterinarian. Species, breed, route, formulation, age, kidney and liver function and the product label all change the dose, and cats differ for many drugs. Inside the app each clinic's vet sets the dose rates and maximums in its own drug master.
Does the calculator in Pet Clinic Software do more than this page?
Yes. Inside Pet Clinic Software it uses the strength from your drug master, warns on unconvertible units, a rate above your maximum mg/kg, a weight older than 30 days or 20 % off the last record, and allergy flags, and needs the vet's verification tick (plus a reason to override a warning) before it logs the dose to the chart and, for drugs you flag as controlled, the register. Stock is deducted when the item is billed.
Can the calculator replace the vet's check?
No. Calculations never replace a veterinarian's judgement. The checks catch common errors, such as a stale weight or the wrong strength, but the vet confirms the drug, concentration, weight and dose before anything is given, and the clinic sets its own protocols.
Can I calculate for tablets?
Yes. Enter the tablet strength in mg as the "strength" and read the result as the number of tablets instead of ml. For example, 5 mg/kg for a 10 kg dog from 50 mg tablets gives 50 mg, which is 1 tablet. Round to a fraction the tablet can actually be split into.
Dose from today's weight, every time
Pet Clinic Software reads the weight, knows the vial and logs the register. 14-day free trial, no card.