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NSAID / Antiplatelet · For Dogs

Aspirin dosage reference for dogs (Acetylsalicylic Acid)

This page's standard weight-based reference is 10 mg per kg (4.54 mg per lb), with every 12 hours recorded as the reference frequency. Use the calculator to see the arithmetic for your dog's weight, then confirm the indication, product, and actual dose with a veterinarian.

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

Weight-based calculator estimate from the references listed on this page. This page has not been independently DVM-reviewed — 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.

Each medication page lists the references recorded for its data. The calculator math and editorial presentation are maintained by PetDosageChart; a page is independently DVM-reviewed only when a named reviewer byline appears. See our methodology and limitations.

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 weight-based reference chart for dogs

Scroll sideways to see full table

Weight Lower Reference Standard Reference Upper Reference Frequency
5 lbs (2.3 kg) 11.5 mg 23.0 mg 34.5 mg every 12 hours
10 lbs (4.5 kg) 22.5 mg 45.0 mg 67.5 mg (81mg tablet) every 12 hours
15 lbs (6.8 kg) 34.0 mg 68.0 mg (81mg tablet) 102.0 mg every 12 hours
20 lbs (9.1 kg) 45.5 mg 91.0 mg (81mg tablet) 136.5 mg every 12 hours
25 lbs (11.3 kg) 56.5 mg 113.0 mg 169.5 mg (2 × 81mg) every 12 hours
30 lbs (13.6 kg) 68.0 mg (81mg tablet) 136.0 mg 204.0 mg every 12 hours
40 lbs (18.1 kg) 90.5 mg (81mg tablet) 181.0 mg (2 × 81mg) 271.5 mg every 12 hours
50 lbs (22.7 kg) 113.5 mg 227.0 mg (3 × 81mg) 340.5 mg (4 × 81mg) every 12 hours
60 lbs (27.2 kg) 136.0 mg 272.0 mg 408.0 mg (5 × 81mg) every 12 hours
70 lbs (31.7 kg) 158.5 mg (2 × 81mg) 317.0 mg (4 × 81mg) 475.5 mg (6 × 81mg) every 12 hours
80 lbs (36.3 kg) 181.5 mg (2 × 81mg) 363.0 mg 544.5 mg every 12 hours
90 lbs (40.8 kg) 204.0 mg 408.0 mg (5 × 81mg) 612.0 mg every 12 hours
100 lbs (45.4 kg) 227.0 mg (3 × 81mg) 454.0 mg 681.0 mg every 12 hours
120 lbs (54.4 kg) 272.0 mg 544.0 mg 816.0 mg (10 × 81mg) every 12 hours
150 lbs (68 kg) 340.0 mg (4 × 81mg) 680.0 mg 1020.0 mg every 12 hours

Parenthetical tablet amounts are arithmetic comparisons only. They do not account for scoring, release type, concentration, product labeling, or whether this medication is appropriate for an individual animal.

By Weight

Aspirin reference by dog weight

Choose a common weight to open its optional reference page. Use the main medication calculator for a different exact weight.

Common-weight pages are convenience views of the same educational reference, not separate medical recommendations.

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Why an Over-the-Counter Product Still Needs Veterinary Direction

The calculator applies a 10 mg/kg standard reference, but it cannot determine whether aspirin is appropriate, whether another pain medicine is safer, or how the dog’s kidney, liver, stomach, clotting status, and current medications change the risk. Easy retail access does not make aspirin a routine home treatment for dogs.

Do not combine aspirin with another NSAID, a corticosteroid, or an anticoagulant unless the veterinarian managing the dog explicitly directs it. Tell the clinic when the last dose of every pain or anti-inflammatory medicine was given before switching products.

Coating, buffering, or a “baby aspirin” label does not establish a safe veterinary product or schedule. Use only the exact product and duration the veterinarian specifies, and treat vomiting blood, black stools, unusual bruising, collapse, or marked weakness as urgent warning signs.

How to Give Acetylsalicylic Acid to Your Dog

Give aspirin only when a veterinarian has specified the exact product, amount, schedule, and duration. Food or a coated product does not remove the risk of ulceration or bleeding. Never give aspirin to a cat without specific veterinary instruction.

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.

Use This Guide Safely · 08

What weight alone cannot tell you

The calculator performs one narrow job: it multiplies your dog's weight by the lower, standard, and upper mg/kg values recorded for Aspirin. It cannot decide whether this drug, indication, formulation, or schedule is appropriate for an individual animal.

Context in this medication record

Commonly listed uses
mild pain relief, inflammation, fever reduction, blood clot prevention
Recorded forms
tablet, buffered tablet
Reference timing
every 12 hours; onset 30-60 minutes; duration 12 hours

Individual checks a calculator cannot perform

  • Confirm the diagnosis and the reason this medication is being considered.
  • Match the exact product, concentration, route, and whether a tablet may be split.
  • Account for age, pregnancy, organ function, genetics, allergies, and prior reactions.
  • Review every prescription, over-the-counter product, and supplement your pet takes.

Recorded cautions

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

Recorded interactions

other NSAIDs; corticosteroids; anticoagulants; methotrexate; furosemide.

These lists reproduce the structured record used by this page and may not be exhaustive. Show your veterinarian the product label and your dog's complete medication list before acting on a number.

Related · 08

Related medications for dogs

Sources · 09

Sources & references

The structured medication record behind this page names the references below. The links open the publisher or official resource; they do not turn this page into a prescription for an individual animal.

Source names are shown at the record level; passage-level page and label citations are still being added. Read our methodology and limitations.

Transparency · 11

How this page was made

This page's structured medication record includes Plumb's Veterinary Drug Handbook among its source names. PetDosageChart applies the record's mg/kg values to the entered weight and presents the arithmetic result. A source record is not the same as an individualized prescription or an independent clinical review.

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 shows an arithmetic comparison with recorded tablet sizes. That comparison does not determine whether a tablet is scored, splittable, or appropriate for your pet.
Editorial owner
Prepared and maintained by the PetDosageChart editorial team, a software-led publisher and not a veterinary practice.
DVM review status
Not independently DVM-reviewed. A named reviewer and review date appear here only after a confirmed review.

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

Safety · 10

More resources