Size & Fit Guide
Choosing the right size helps keep your pet comfortable and makes the product easier and safer to use.
Because sizing may vary between products, always compare your pet’s measurements with the size chart shown on the individual product page. Do not choose a size based only on breed, age, or weight.
Before You Measure
For the most accurate result:
- Use a soft measuring tape;
- Measure your pet while standing naturally;
- Keep the tape comfortably close without pulling it tight;
- Measure twice to confirm the result; and
- Record measurements in both inches and centimeters if possible.
If your pet is between sizes, follow the sizing recommendation on the applicable product page. In most cases, choosing the larger size provides more room for comfort and adjustment.
How to Measure Your Pet
Neck Circumference
Measure around the lower part of the neck where a collar or harness would naturally sit.
Leave enough room to slide approximately two fingers between the measuring tape and your pet’s neck.
Chest Girth
Measure around the widest part of the chest, usually directly behind the front legs.
Chest girth is generally the most important measurement when selecting a harness. Do not rely only on neck size or weight.
Back Length
Measure from the base of the neck, between the shoulder blades, to the base of the tail.
Do not measure from the top of the head or include the tail.
Pet Height
Measure from the floor to the top of your pet’s head while your pet is standing naturally.
For carrier selection, also measure the height from the floor to the top of the shoulders.
Pet Length
Measure from the front of the chest to the base of the tail.
This measurement is especially important for pet carriers, car seats, beds, and travel bags.
Pet Weight
Weigh your pet using a pet scale or a household scale.
To use a household scale:
- Weigh yourself;
- Weigh yourself while holding your pet; and
- Subtract your weight from the combined weight.
Weight limits are important, but they should always be considered together with your pet’s body measurements.
Harnesses and Leash Sets
When choosing a dog or cat harness, measure:
- Neck circumference;
- Chest girth; and
- Pet weight.
Chest girth should be your primary reference.
A properly fitted harness should:
- Sit securely without pressing into the neck;
- Allow approximately two fingers beneath the straps;
- Stay in place without rotating excessively;
- Allow natural walking and shoulder movement; and
- Be snug enough that your pet cannot back out.
After adjusting the harness, check every strap before use.
If your pet is still growing, choose a size that fits securely now and offers sufficient adjustment room. Do not use an oversized harness that your pet can escape from.
Pet Carriers and Backpacks
When choosing a pet carrier, sling, or backpack, measure:
- Pet length;
- Pet height;
- Chest or body width; and
- Pet weight.
Your pet should have enough room to sit, lie down, and turn around comfortably when the carrier design allows.
Do not select a carrier based only on the maximum weight shown. Two pets of the same weight may have very different body shapes and space requirements.
Compare your pet’s measurements with the carrier’s internal dimensions, not only its external dimensions.
For airline travel, always check the airline’s current requirements before departure. Airline rules, accepted carrier dimensions, and weight limits vary by airline, aircraft, route, and cabin class. AtouPet cannot guarantee that a carrier will be accepted on every flight.
Sling and Front Carriers
For sling and front-facing carriers, check:
- Your pet’s weight;
- Body length;
- Chest size; and
- The carrier’s recommended weight capacity.
Your pet should sit securely without excessive compression or room to jump out.
Always attach the internal safety tether to a properly fitted harness—not directly to a collar.
Some sling carriers are designed for short trips and daily outings rather than extended travel.
Dog Car Seats and Booster Seats
When choosing a car seat, measure:
- Pet length;
- Sitting height;
- Body width; and
- Pet weight.
The seat should provide enough room for your dog to sit or lie down without being tightly compressed.
Check both:
- The product’s internal dimensions; and
- The available space in your vehicle.
A pet car seat should be installed according to the product instructions and used with an appropriate harness and restraint when provided. Do not attach a vehicle restraint directly to your pet’s collar.
Recovery Collars
For a recovery collar, measure:
- Neck circumference; and
- The distance from the neck to the end of the nose.
The collar should fit securely without restricting breathing or swallowing.
For effective coverage, the outer edge of the recovery collar should normally extend far enough to reduce your pet’s ability to reach the affected area.
Because wound locations and pet flexibility vary, monitor your pet after fitting the collar. A soft recovery collar may not be suitable for every injury or surgical site. Consult your veterinarian if you are unsure.
What If Your Pet Is Between Sizes?
If your pet falls between two sizes:
- Choose the larger size when the product has adjustable straps;
- Prioritize chest girth for harnesses;
- Prioritize internal dimensions for carriers and car seats;
- Check that the product does not exceed its stated weight limit; and
- Contact us before ordering if you remain unsure.
A larger size is not always safer. Harnesses and escape-resistant products must still fit securely enough to prevent slipping or backing out.
Fit Check After Delivery
Before regular use:
- Let your pet inspect the product;
- Adjust every strap gradually;
- Check for pressure around the neck, chest, legs, and shoulders;
- Confirm that your pet can breathe and move naturally;
- Check that your pet cannot escape or slip out; and
- Test the product indoors before using it outdoors or in a vehicle.
Stop using the product if your pet shows difficulty breathing, restricted movement, unusual stress, rubbing, or discomfort.
Recheck the fit regularly, especially for growing pets or after weight changes.
Important Sizing Notice
Product sizing is not standardized across all AtouPet products. A size Medium in one product may not be the same as a size Medium in another.
Always use the measurements and size chart provided on the specific product page before ordering.
Breed and weight recommendations are general references only and cannot guarantee fit because pets of the same breed or weight may have different body proportions.
Need Help Choosing a Size?
If you are unsure which size to choose, email us before placing your order.
Please include:
- The product name or link;
- Your pet’s breed;
- Your pet’s weight;
- Neck circumference;
- Chest girth;
- Back or body length; and
- A standing side-view photo, if helpful.
Email: support@atoupet.com
Response time: Usually within 1–3 business days