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PawCurve

Dog Age Chart

Built from your breed's own measured lifespan across 155 breeds — not from a size bucket, and not from the chart everyone copies, which we couldn't trace to any source.

The chart changes with the breed, because lifespan does — from 5.4 years to 15.4 across the 155 breeds in the study. A single "dog age chart" can't be right for all of them.

Sex

Dog's ageLife stage (AAHA)% of expected lifeHuman years (Wang 2020)The unsourced chart says

The last column is the table you'll find everywhere else — 15 for year one, +9 for year two, then a size coefficient. We show it greyed out because we went looking for its source and there isn't one; the documents it's credited to don't contain it. It's here so you can see what you'd have been told, not because we think it's right.

Why this chart looks different from every other one

Search "dog age chart" and you'll get the same table everywhere: 15 human years at one, 24 at two, then +4 a year for a small dog and up to +6.5 for a giant. Clean, memorable, universally cited to the AVMA or the AAHA.

We went to check it, because we were going to publish it too. It isn't in either document.

"For practical purposes, rather than attempt to calculate age equivalents to humans, the task force suggests that life stage be defined both by age and characteristics (Table 1). Life stage divisions, although arbitrary, provide a framework for creating individualized plans for preventive care specific to each dog's needs at the appropriate time."
— 2019 AAHA Canine Life Stage Guidelines. Searching the full text for "human years" returns nothing.

The body cited as the authority for the chart considered making one and decided not to. The AVMA doesn't publish it either — it publishes lifespan ranges by size, and on the same page it debunks the × 7 rule that the chart was invented to replace. Different sites even use different coefficients (+4/+5/+6/+7 is as common as +4/+5/+5.5/+6.5). Real standards don't come in variants.

So we had a choice: print it anyway because it's what people expect, or build a chart out of things that actually have sources. You're looking at the second one. The familiar numbers are still in the last column, greyed out, so you can see what you'd have been told.

Size is the wrong question

Every dog age chart sorts by size. Here's what the data says that's worth, from a study of 584,734 dogs:

Sorted by…Median lifespan rangeSpread
Size (small → large)12.7 → 11.9 years0.8 years
Muzzle (medium → flat)12.8 → 11.2 years1.6 years
Breed15.4 → 5.4 years10 years

Ten years versus ten months. Sorting dogs into small, medium and large captures almost none of what varies between them. It's a lossy compression of breed — and it's the only input the traditional chart has.

It matters most for the dogs where being wrong costs the most. A seven-year-old Cane Corso is already senior — 86% of the way through a median 8.1-year life. The familiar chart calls it "49 in human years", which reads as comfortably middle-aged. That's not a rounding difference; it's the difference between starting twice-yearly check-ups and not.

How to read the columns

Life stage is the AAHA's, and it's the answer they actually endorse: puppy, young adult, mature adult, senior — where senior means the last 25% of expected life. It's the column worth acting on, because it maps to something you'd do differently.

% of expected life is our arithmetic: the dog's age over its breed's median. We're showing the working rather than presenting it as something we looked up.

Human years is Wang et al. (2020) —16 × ln(dog age) + 31 — the one conversion with a paper behind it. Hold it loosely: 104 dogs, mostly Labradors, and the authors say so themselves.

The last column is the chart you came for. We're not hiding it. We're just not going to tell you it's true.

Frequently asked questions

What is the dog age chart?
This chart separates the sources instead of blending them. Life stages come from AAHA guidance, expected lifespan comes from breed-level data, and the human-year estimate comes from the one peer-reviewed methylation formula. The familiar chart — 15 human years for year one, 24 by year two, then +4 to +6.5 a year by size — is widely credited to the AVMA or AAHA, but we downloaded both documents and searched them; neither contains those coefficients. The AAHA guidelines mention "human years" zero times and explicitly decline to make the conversion.
Why does the chart change when I pick a breed?
Because lifespan does — enormously. Across the 155 breeds in the study behind this chart, medians run from 5.4 years (Caucasian Shepherd Dog) to 15.4 (Lancashire Heeler). That's a ten-year spread. Meanwhile the size classes everyone uses span just 0.8 years. A chart that asks "small, medium or large?" is throwing away almost all of the signal before it starts. Yours asks for the breed.
How many human years is 1 dog year?
The only peer-reviewed answer is 31 — from human age = 16 × ln(dog age) + 31, Wang et al. (2020), based on DNA methylation. Which sounds absurd until you remember a one-year-old dog can already reproduce. The formula's own authors are candid about its limits: it comes from 104 dogs that were "primarily Labrador retrievers", and they warn that other breeds "could yield different age-translation functions". So it takes no account of your dog's size. We show it, we label it, and we don't dress it up as more than it is.
Why is the familiar chart in the last column, greyed out?
We show it for comparison because many readers know it already. The two estimates happen to cross over: for a 10-year-old large dog the old chart says 68 and Wang says 68 as well. But for a 3-year-old the old chart says 30 while Wang says 49 — they disagree by nineteen years, and only one of them has a paper behind it.
When does my dog become a senior on this chart?
When it reaches the last 25% of its expected lifespan — that's the AAHA's own definition, and it's a proportion, not a birthday. That's why the senior rows shift as you change the breed. For a Labrador (median 13.1 years) it's around 9.8; for a Cane Corso (8.1) it's around 6.1. A seven-year-old Cane Corso is already senior — 86% of the way through its expected life — which the familiar chart, telling you it's "49 in human years", completely misses. More in our senior dog age guide.
What is this chart built from?
Three sourced things, kept separate. Lifespan: McMillan et al. (2024), Scientific Reports 14:531 — 584,734 UK dogs, 155 breeds, peer-reviewed, CC BY 4.0. Life stages: the 2019 AAHA Canine Life Stage Guidelines. Human years: Wang et al. (2020), Cell Systems 11(2). We never blend the last one into the first two — merging a stage model with a human-age number is precisely the step AAHA refused to take.

Related

Sources last checked 2026-07-17. Lifespan: McMillan et al. (2024), Scientific Reports 14:531, CC BY 4.0 — a UK population, so medians are conditional on dogs entering those records. Life stages: 2019 AAHA Canine Life Stage Guidelines (JAAHA 2019;55:267–290). Human-age conversion: Wang et al. (2020), Cell Systems 11(2):176–185. Full detail, and the checks we ran before claiming a document doesn't say something, on our methodology page.