How big is a Jack Russell Terrier?
Up to 30 cm (12 in) at the shoulder, per the FCI breed standard: here it is to scale next to a person, with its weight, how long it lives and when it becomes a senior.
To scale, next to a person
Zoomed ×2: here you see the man up to 95 cm (37 in) off the ground
Photo: Pleple2000 (CC BY-SA 3.0)
The breed in numbers
- Height
- 25-30 cm
- Weight
- 5-6 kg (11-13 lb)
- Median lifespan
- 13.3 years
- Senior from
- 8-11 years
- FCI group
- terriers (FCI 345)
- Calories a day
- 400 kcal
In the standard: In the standard, weight goes with height: 1 kg for every 5 cm, so about 5 kg (11 lb) at 25 cm and 6 kg (13 lb) at 30 cm.
Frequently asked questions
How tall is a Jack Russell Terrier?
25 to 30 cm (10 to 12 in) at the shoulder for males, according to the official FCI breed standard (no. 345). In the standard, weight goes with height: 1 kg for every 5 cm, so about 5 kg (11 lb) at 25 cm and 6 kg (13 lb) at 30 cm.
How much does a Jack Russell Terrier weigh?
5-6 kg (11-13 lb), according to the official FCI standard.
How long does a Jack Russell Terrier live?
The median lifespan is 13.3 years, from a 2024 study of 584,734 dogs in the UK (McMillan et al.). Half the dogs of the breed lived longer, half shorter.
When is it a senior?
The AVMA says a dog is a senior in the last quarter of its expected life: for this breed’s weight, from 8–11 years old. From then on, a vet checkup at least twice a year.
How much should it eat?
A spayed or neutered adult weighing 5.5 kg (12 lb) needs about 400 calories a day, by the Pet Nutrition Alliance formula. The amount depends on the calories in its food: work it out from the label.
How old is it in human years?
By the formula from a 2020 DNA study: at 1 year it’s like a 31-year-old person, at 3 like a 49-year-old, at 7 like 62, at 12 like 71. The formula was found in Labradors: for other breeds it’s an estimate.
Compare it with other breeds All 42 breeds All the pets next to a person
For your dog
Always ask your vet: this site helps you understand, it doesn’t replace a checkup.
Sources
- Fédération Cynologique Internationale (FCI), breed standards (checked on October 9, 2026)
- McMillan K. M. et al., “Longevity of companion dog breeds: those at risk from early death,” Scientific Reports 2024 (CC BY 4.0) (checked on October 6, 2026)
- AVMA, “Caring for senior cats and dogs” (checked on October 6, 2026)
- Pet Nutrition Alliance, “Calculating Calories Based on Pet Needs” (checked on October 6, 2026)
- Wang T. et al., “Quantitative Translation of Dog-to-Human Aging by Conserved Remodeling of the DNA Methylome,” Cell Systems 2020 (checked on October 6, 2026)