Dog Age Calculator: Dog Years to Human Years

Move the slider, pick your dog’s size and see their age in human years and their life stage. Free, instant and adjusted for size, because big dogs age faster than small ones.

Dog age calculator

77human years

Life stage

Senior

Joint support, vet checks twice a year and a calorie plan matched to lower activity.

My dog’s age12 years

Size

Get a care plan for my 12-year-old dog

Estimate based on common size-adjusted age charts. Every dog ages differently, so ask your vet.

Quick answer

A dog’s first year equals about 15 human years and the second about 9 more. After that, small dogs age about 4 human years per year, medium dogs about 4.5 and large dogs about 5 or more. The “multiply by 7” rule is a myth.

How dog years to human years works

Dogs grow up fast: by their second birthday most are fully adult. After that, size matters. Large and giant breeds age faster and are usually considered senior sooner than small breeds.

When is a dog considered a senior?

Most dogs are considered seniors at around 7 years old. Large dogs often reach their senior years at about 6 or 7, medium dogs at about 8 and small dogs at about 10.

Once your dog reaches their senior years, the Senior Dog Hub shows what changes to look for, and the free readiness quiz gives you a personal care score.

Dog years to human years chart

Dog age in human years by size
Dog age	Small	Medium	Large
1	15	15	15
2	24	24	24
3	28	29	29
4	32	33	35
5	36	38	40
6	40	42	45
7	44	47	51
8	48	51	56
9	52	56	61
10	56	60	66
11	60	65	72
12	64	69	77
13	68	74	82
14	72	78	88
15	76	83	93
16	80	87	98

Approximate values from common size-adjusted charts. Small: under about 10 kg / 22 lb. Medium: about 10–25 kg / 22–55 lb. Large: over about 25 kg / 55 lb.

Dog age questions

Is one dog year equal to seven human years?

No. The 7-to-1 rule is a myth. Dogs mature very quickly in their first two years, then age at a pace that depends on their size. Larger dogs age faster than small ones.

How old is a 10-year-old dog in human years?

Using common size-adjusted charts, a 10-year-old small dog is about 56 in human years, a medium dog about 60 and a large dog about 66. Use the calculator above for your dog's exact age and size.

When is a dog considered a senior?

Most dogs are considered seniors at around 7. Large and giant breeds can be senior at about 6, small breeds at about 10.

Why do large dogs age faster than small dogs?

Scientists are still studying why, but large and giant breeds generally have shorter lifespans and show signs of aging earlier than small breeds.

Dog age	Small	Medium	Large
1	15	15	15
2	24	24	24
3	28	29	29
4	32	33	35
5	36	38	40
6	40	42	45
7	44	47	51
8	48	51	56
9	52	56	61
10	56	60	66
11	60	65	72
12	64	69	77
13	68	74	82
14	72	78	88
15	76	83	93
16	80	87	98

Dog age	Small	Medium	Large
1	15	15	15
2	24	24	24
3	28	29	29
4	32	33	35
5	36	38	40
6	40	42	45
7	44	47	51
8	48	51	56
9	52	56	61
10	56	60	66
11	60	65	72
12	64	69	77
13	68	74	82
14	72	78	88
15	76	83	93
16	80	87	98

Dog age	Small	Medium	Large
1	15	15	15
2	24	24	24
3	28	29	29
4	32	33	35
5	36	38	40
6	40	42	45
7	44	47	51
8	48	51	56
9	52	56	61
10	56	60	66
11	60	65	72
12	64	69	77
13	68	74	82
14	72	78	88
15	76	83	93
16	80	87	98