Dog age chart

Find your dog’s age in the left column and read across to their size. Small dogs are 20 lb or less, medium 21–50 lb, large 51–100 lb and giant over 100 lb. Values come from the size-based vet chart.

Dog years to human years. Small is 20 lb or less, Medium is 21–50 lb, Large is 51–100 lb, Giant is over 100 lb.
Dog age	Small	Medium	Large	Giant
1 year	15	15	15	12
2 years	24	24	24	22
3 years	28	28	28	31
4 years	32	32	32	38
5 years	36	36	36	45
6 years	40	42	45	49
7 years	44	47	50	56
8 years	48	51	55	64
9 years	52	56	61	71
10 years	56	60	66	79
11 years	60	65	72	86
12 years	64	69	77	93
13 years	68	74	82	100
14 years	72	78	88	107
15 years	76	83	93	114
16 years	80	87	99	121
17 years	84	91	105	128
18 years	88	95	111	135
19 years	92	99	117	142
20 years	96	103	123	149

The default is the size-based vet chart. See how pet age is calculated.

Under one year

Need months or a specific breed? Use the dog age calculator.

Dog life stages

Life stage	Age
Puppy	Birth to 12 months (18 months for large and giant breeds)
Young adult	Until about 3 years old
Mature adult	From 3 years until the last quarter of expected lifespan
Senior	The last 25% of expected lifespan: about 6½ years for giant dogs up to about 10½ for small dogs

FAQ

How old is a 1-year-old dog in human years?

About 15 for small, medium and large dogs, and 12 for giant dogs.

Does a dog’s age in human years change with size?

Yes. After the first two years, bigger dogs age faster. A 10-year-old small dog is about 56 in human years and a giant dog about 79.