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NSAID / Antiplatelet · For Dogs

How much Aspirin (Acetylsalicylic Acid) can I give my dog?

Standard Aspirin dose for dogs is 10 mg per kg (4.54 mg per lb), given every 12 hours. Use the calculator below for your dog's exact weight, or jump to the weight-by-weight chart.

Onset
30-60 minutes
Duration
12 hours
Class
NSAID / Antiplatelet

Calculator estimate from Plumb’s Veterinary Drug Handbook. Independent DVM review is being added page by page — see our methodology .

This information is for educational purposes only. Always consult your veterinarian before giving medication to your pet. Do not use this calculator for emergencies, overdoses, pregnancy, very young animals, very old animals, pets with liver/kidney disease, or pets taking multiple medications.

Dosage data is sourced from Plumb's Veterinary Drug Handbook and cross-referenced with Merck Veterinary Manual and DailyMed where applicable. Independent DVM review is being added page by page. See our methodology.

Acetylsalicylic Acid (often known by brand names such as Aspirin and Bufferin) is an NSAID / antiplatelet commonly used in veterinary medicine for mild pain relief, inflammation, fever reduction, and blood clot prevention. Understanding the correct dosage, administration, and potential side effects of Acetylsalicylic Acid is critical for your dog’s safety and well-being.

A typical Acetylsalicylic Acid dose for dogs is around 10 mg/kg every 12 hours, within a usual range of 5-15 mg/kg. Available forms include tablet and buffered tablet.

Calculator Warning: Use this only as an educational estimate. Your veterinarian may prescribe a different dose based on your pet’s condition, age, weight, other medications, and medical history.

Acetylsalicylic Acid Dosage Calculator for Dogs

Enter your dog’s weight below to estimate the Acetylsalicylic Acid dose from the 10 mg/kg guideline. Your veterinarian may adjust it for your dog’s age, condition, and other medications, so treat the result as an educational starting point, not a prescription.

Dosage Calculator · 01

Enter your dog's weight

Quick Dosage Chart

Typical Acetylsalicylic Acid amounts for common dog weights, for quick reference:

Dosage Chart · 02

Aspirin dosage for dogs by weight

Scroll sideways to see full table

Weight Low Dose Standard Max Safe Frequency
5 lbs (2.3 kg) 11.5mg 23mg 34.5mg every 12 hours
10 lbs (4.5 kg) 22.5mg 45mg 67.5mg (81mg tablet) every 12 hours
15 lbs (6.8 kg) 34mg 68mg (81mg tablet) 102mg every 12 hours
20 lbs (9.1 kg) 45.5mg 91mg (81mg tablet) 136.5mg every 12 hours
25 lbs (11.3 kg) 56.5mg 113mg 169.5mg (2 × 81mg) every 12 hours
30 lbs (13.6 kg) 68mg (81mg tablet) 136mg 204mg every 12 hours
40 lbs (18.1 kg) 90.5mg (81mg tablet) 181mg (2 × 81mg) 271.5mg every 12 hours
50 lbs (22.7 kg) 113.5mg 227mg (3 × 81mg) 340.5mg (4 × 81mg) every 12 hours
60 lbs (27.2 kg) 136mg 272mg 408mg (5 × 81mg) every 12 hours
70 lbs (31.7 kg) 158.5mg (2 × 81mg) 317mg (4 × 81mg) 475.5mg (6 × 81mg) every 12 hours
80 lbs (36.3 kg) 181.5mg (2 × 81mg) 363mg 544.5mg every 12 hours
90 lbs (40.8 kg) 204mg 408mg (5 × 81mg) 612mg every 12 hours
100 lbs (45.4 kg) 227mg (3 × 81mg) 454mg 681mg every 12 hours
120 lbs (54.4 kg) 272mg 544mg 816mg (10 × 81mg) every 12 hours
150 lbs (68 kg) 340mg (4 × 81mg) 680mg 1020mg every 12 hours

By Weight

Aspirin dose by dog weight

Pick your dog's weight to jump to a dedicated page with the dose, frequency, safety notes, and FAQ for that size.

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How to Give Acetylsalicylic Acid to Your Dog

Always use buffered or enteric-coated aspirin to reduce stomach irritation. Give with food. Baby aspirin (81 mg) is often preferred for smaller dogs. Never give aspirin to cats without specific veterinary instruction, as cats metabolize salicylates very slowly.

It is generally recommended to give Acetylsalicylic Acid with food to help reduce stomach upset. It may interact with other NSAIDs, corticosteroids, anticoagulants, methotrexate, and furosemide.

Side Effects and Safety

Common side effects include stomach upset, decreased appetite, vomiting, and diarrhea. More serious side effects can occur, such as gastrointestinal ulceration, bleeding disorders, kidney damage, and liver toxicity.

Cautions · 12

When Aspirin should be used with caution or avoided

Some dogs should not take Aspirin, or need a different dose and closer monitoring. Tell your veterinarian about your pet's full health history and every other medication or supplement they take before giving Aspirin.

  • cats
  • puppies under 6 months
  • dogs with bleeding disorders
  • use with other NSAIDs or corticosteroids
  • kidney or liver disease

Interactions · 13

Aspirin drug interactions

Aspirin can interact with other drugs. This list is not complete — always give your veterinarian a full list of your dog's medications and supplements.

other NSAIDs
corticosteroids
anticoagulants
methotrexate
furosemide

Calculator Limits · 14

When not to use this calculator

This calculator gives a general educational estimate for a healthy adult dog at a known weight. Do not rely on it in these situations — talk to your veterinarian instead:

  • In an emergency, or after accidental ingestion or a suspected overdose
  • For pregnant or nursing pets
  • For very young or very old dogs
  • For pets with liver disease, kidney disease, or another chronic illness
  • For pets taking several medications at once
  • When you are not sure of your dog's current, accurate weight
  • For combination products that contain additional active ingredients

Overdose · 15

Suspected overdose: what to do

If you think your dog had too much Aspirin, or swallowed any medication by accident, act right away. Do not wait for symptoms to appear.

  • Call your veterinarian or the nearest emergency animal hospital.
  • ASPCA Animal Poison Control Center: (888) 426-4435
  • Pet Poison Helpline: (855) 764-7661

A consultation fee may apply to the poison hotlines. Have the medication packaging ready, and note how much your pet may have taken and when. Do not try to make your pet vomit unless a veterinarian tells you to.

When to Call the Vet

If your dog experiences any of the following, contact your veterinarian or an emergency clinic immediately:

Frequently Asked Questions

Frequently Asked · 07

Questions about this medication

Can I give my dog aspirin for pain?
Aspirin can be given to dogs for short-term pain relief, but it is not the safest NSAID choice. Veterinary-specific NSAIDs like carprofen or meloxicam are preferred for dogs because they have fewer gastrointestinal side effects. Always consult your vet before giving aspirin.
How much aspirin can I give my dog?
The typical dose is 5-10 mg per kilogram of body weight, given every 12 hours. For a 30 lb (14 kg) dog, this would be about one baby aspirin (81 mg). Always use the lowest effective dose and give with food.
Is baby aspirin safe for dogs?
Baby aspirin (81 mg) is commonly used for dogs due to its lower dose, which allows for more precise dosing in small to medium dogs. However, "safe" is relative — aspirin carries risks of GI ulceration even at low doses, so veterinary-specific NSAIDs are generally preferred.
Can I give my dog aspirin every day?
Daily aspirin use in dogs should only be done under veterinary supervision. Long-term use increases the risk of gastrointestinal ulceration, bleeding, and kidney problems. Your vet may prescribe daily low-dose aspirin for specific conditions like blood clot prevention.

Related · 08

Related medications for dogs

Sources · 09

Sources & references

The dosage information on this page is compiled from the following veterinary and pharmaceutical references:

  • Plumb's Veterinary Drug Handbook — the standard veterinary pharmacology reference used by veterinarians worldwide.
  • Merck Veterinary Manual — a trusted, peer-reviewed resource for veterinary professionals and pet owners.
  • DailyMed (FDA Drug Labels) — official FDA-approved drug labeling and prescribing information for Acetylsalicylic Acid.

Read more about our methodology and how we calculate dosages.

Transparency · 11

How this page was made

Sourced from Plumb's Veterinary Drug Handbook, the reference used in US vet schools. Every dose, frequency, and tablet count on this page is generated from that data, then checked against the published references below.

Sources cited
  • Plumb's Veterinary Drug Handbook
  • Merck Veterinary Manual
Calculator formula
Doses scale linearly from a standard basis of 10 mg per kg (4.54 mg per lb) of body weight, given every 12 hours. The calculator multiplies that basis by your dog's weight and rounds to the closest available tablet size.
Last-reviewed status
Independent DVM review is being added page by page.

More on our methodology and editorial process — how we source, calculate, and review dogs dosage data.

Safety · 10

More resources