Pet Size Guide and Product Fit Guide (US Measurements)

Finding the perfect fit for your pet starts here!

At Sowley for Pets, we understand that no two pets are alike. That’s why we’ve created this all-in-one sizing guide to help you choose the right products—whether it's a cozy sweater, a secure harness, a roomy cage, or the right-size tank.

Dog Size Guide

Measure:

  • Neck Circumference: Where a collar would naturally sit.
  • Chest Girth: Around the widest part of the ribcage.
  • Back Length: From the base of the neck to the start of the tail.
  • Weight: Helpful for general sizing.

Size

Neck (inches)

Chest Girth (inches)

Back Length (inches)

Weight (lbs)

XS

6–9

10–14

8–10

Up to 5 lbs

S

8–12

14–18

10–12

6–10 lbs

M

12–16

18–24

12–16

11–25 lbs

L

16–20

24–30

16–20

26–50 lbs

XL

20–26

30–36

20–26

51–75+ lbs

Tip: Always choose the larger size if your dog is between sizes, especially for apparel or harnesses.

Cat Size Guide

Measure:

  • Neck: Where the collar would rest.
  • Chest Girth: Just behind the front legs.
  • Back Length: Base of neck to base of tail.
  • Weight: Especially for carriers and clothing.

Size

Neck (inches)

Chest Girth (inches)

Back Length (inches)

Weight (lbs)

S

6–8

10–14

9–11

Under 8 lbs

M

8–10

14–18

11–13

8–12 lbs

L

10–12

18–22

13–15

12–18 lbs

Note: Cats generally prefer looser fits—especially around the neck and legs.

Small Pets (Rabbits, Guinea Pigs, Hamsters)

Rabbit Sizing (for harnesses, carriers)

Size

Weight (lbs)

Chest Girth (inches)

Back Length (inches)

S

2–4

8–10

7–9

M

4–6

10–14

9–11

L

6+

14–18

11–13


Hamsters/Guinea Pigs

Use product-specific measurements like:

  • Cage bar spacing: <0.5 inches
  • Cage minimum sizes:
    • Hamsters: 24" x 12" x 12"
    • Guinea pigs: Minimum 7.5 ft² per pig

Tip: Always go larger when it comes to enclosures—more space = healthier pets.

Birds

Choose cages, toys, and perches based on species and wingspan:

Bird Type

Cage Size (min)

Bar Spacing (inches)

Finches/Canaries

18" x 18" x 24"

3/8" or less

Budgies

20" x 18" x 24"

1/2" or less

Cockatiels

24" x 18" x 24"

1/2" to 5/8"

Conures

24" x 24" x 30"

5/8" to 3/4"

African Greys

36" x 24" x 48"

3/4" to 1"

Note: Bigger is always better for flight space and enrichment.

Fish

Tank size depends on species and adult size. Here's a general guide:

Fish Type

Tank Size (min)

Betta

5 gallons

Tetras

10–20 gallons

Goldfish

20+ gallons

Cichlids

30+ gallons

Community tank

20–55+ gallons

Tip: Use 1 inch of fish per gallon as a very rough rule—but always research species compatibility and filtration needs.

Ponds & Pond Pumps

Pond Sizing:

  • Small Pond: 200–500 gallons
  • Medium Pond: 500–1,000 gallons
  • Large Pond: 1,000+ gallons

Pump Sizing:

  • Your pump should circulate the entire pond volume once per hour.
    Example: For a 500-gallon pond, you need a 500 GPH (gallons per hour) pump.

Tip: Add extra GPH if you have waterfalls or need extra filtration power.

Reptiles & Turtles

Tank Size Based on Adult Length:

Pet Type

Tank Size (min)

Notes

Leopard Gecko

20-gallon tank

Prefer floor space

Bearded Dragon

40-gallon tank

More for adults

Corn Snake

20–40 gallon tank

Secure lid required

Turtles (4–6")

40–55 gallon tank

Need water & basking area

Turtles (6"+)

75+ gallon tank

Bigger is better for swimming space

Tip: Always match lighting, temperature, and humidity requirements to your species.

General Measuring Tips

  • Use a soft measuring tape.
  • Measure when your pet is calm and standing naturally.
  • Compare with product-specific charts if available.
  • When in doubt—size up, especially for apparel or enclosures.

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