Boston Terrier age in human years

Boston Terriers are a small breed. Here is the full age chart and what each stage means.

Updated October 2026Numbers calculated for this page

Boston Terriers are a small breed (typically 12–25 lb), so they age about 4 human years for every dog year after age two. A 5-year-old Boston Terrier is about 36 in human years, and the senior years usually start around age 9.

11–13 yrstypical life expectancy

68human years at age 13

~9senior years begin

12–25 lbtypical adult weight

Boston Terrier age chart

Dog age	Human years	Life stage
1 year	15	Young adult
2 years	24	Young adult
3 years	28	Mature adult
4 years	32	Mature adult
5 years	36	Mature adult
6 years	40	Mature adult
7 years	44	Mature adult
8 years	48	Mature adult
9 years	52	Senior
10 years	56	Senior
11 years	60	Senior
12 years	64	Senior
13 years	68	Golden years
14 years	72	Golden years
15 years	76	Golden years

Uses the common size-based chart: the first year equals about 15 human years, the second adds about 9, and each year after that adds 4 (small), 5 (medium), 6 (large) or 7 (giant). It is an estimate, not a medical measure.

What each stage means for a Boston Terrier

Young adult (1–3): still learning. Keep training consistent and set the healthy weight now; for a Boston Terrier that is usually within 12–25 lb.
Mature adult (3–8): yearly checkups, dental care and steady exercise. Watch the waistline as activity drops.
Senior (9+): many vets suggest checkups every six months, plus attention to joints, teeth and weight changes.

How much a Boston Terrier eats

A spayed or neutered adult around 18 lb needs roughly 550 calories a day, about 1.5 cups of a typical 380-calorie-per-cup dry food. See the full feeding guide for a 20 lb dog.

Planning the budget? See what a Boston Terrier costs per year.

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Other small breeds

French Bulldog Miniature Poodle Toy Poodle Yorkshire Terrier Cavalier King Charles Spaniel Miniature Schnauzer Shih Tzu Pomeranian Havanese Shetland Sheepdog

Any small dog: see how old a 7-year-old small dog is or try the dog age calculator.

Questions people ask

How old is a 10-year-old Boston Terrier in human years?

About 56, using the small-breed chart.

How long do Boston Terriers live?

Typically 11 to 13 years, though genetics, weight, diet and vet care all matter.

When is a Boston Terrier considered a senior?

Around age 9, roughly the last quarter of the breed's typical lifespan.

The Paw Plan shares general pet care information, not veterinary advice. Figures on this page are estimates calculated from the assumptions shown. Every pet is different, so check with your vet about yours.