Size Guide
Measure Carefully Choose Confidently
A comfortable fit starts with accurate measurements. Use this guide to measure your cat or small dog before choosing a pet carrier, harness, bed or recovery product.
Product dimensions and sizing can vary between designs, so always compare your measurements with the size chart shown on the individual product page.
Basic Pet Measurements
Use a flexible measuring tape and keep your pet standing naturally. Measure without pulling the tape tightly against the body.
Neck Circumference
Measure around the area where a collar naturally sits. Keep the tape level and allow enough room for normal movement and breathing.
Chest Girth
Measure around the widest part of the ribcage, usually just behind the front legs. This is an important measurement for harnesses and recovery wear.
Back Length
Measure from the base of the neck between the shoulder blades to the base of the tail. Do not include the tail in this measurement.
Body Length
For a carrier, measure from the front of the chest or nose area to the base of the tail while your pet is standing naturally.
Standing Height
Measure from the floor to the top of your pet's head or ears, whichever is higher in their normal standing position.
Resting Space
Measure the area your pet uses while lying in a natural sleeping position. This helps when selecting beds, mats and resting spaces.
- Measure your pet at least twice
- Keep the measuring tape level
- Do not pull the tape too tightly
- Allow for thick or long fur
- Record the measurement before shopping
- Use the same unit shown in the product chart
Choose a Size by Product Type
Different products require different measurements. Open the relevant section below before comparing your pet with a product size chart.
Pet Carriers
Measurements to check
- Body length
- Standing height
- Body width at the widest point
- Current body weight
- Carrier internal dimensions when provided
How to choose
Compare your pet's measurements with the usable internal space of the carrier rather than relying only on the external dimensions. Your pet should have enough space to sit, lie down and reposition without being tightly compressed.
Weight limits describe the amount of weight the carrier is designed to hold, but they do not guarantee a comfortable fit. Two pets with the same weight may have very different body lengths and heights.
Travel reminder
Airline and transport requirements vary. Before traveling, confirm the current carrier size, construction and cabin requirements directly with the airline or transport provider. A general product description does not guarantee acceptance on every route or aircraft.
Harnesses and Leash Sets
Measurements to check
- Chest girth at the widest part of the ribcage
- Neck circumference where the harness sits
- Body weight as secondary guidance
How to choose
Chest girth is usually the most important measurement for a harness. Compare both the chest and neck measurements with the specific product chart and confirm that your pet falls within the adjustable range.
As a general starting check, you should usually be able to place approximately two fingers between the harness and your pet without forcing them. The harness should not restrict breathing or movement, but it should also not be loose enough for your pet to back out.
Before outdoor use
Adjust every strap, check all buckles and gently test the fit indoors before attaching the leash outdoors. Pets that are especially flexible, nervous or escape prone may require additional fit checks and supervision.
Pet Beds and Cushions
Measurements to check
- Body length while lying down
- Width of the natural sleeping position
- Usable inner sleeping area
- Overall product dimensions
How to choose
Observe whether your pet normally sleeps curled up or stretched out. Measure the space they naturally use and compare it with the bed's usable inner area.
Raised edges, bolsters and thick padding can reduce the usable sleeping space, so do not rely only on the bed's overall external dimensions.
If your pet is between two sizes or prefers to stretch out, the larger option may provide more comfortable resting space.
Recovery Collars and Recovery Wear
Measurements to check
- Neck circumference
- Chest girth for recovery wear
- Back length for recovery wear
- Collar depth or outer diameter
- Location of the area being protected
Recovery collars
The neck opening should remain secure without restricting breathing or swallowing. The collar must also extend far enough to help prevent your pet from reaching the affected area.
The appropriate collar depth may depend on whether the protected area is near the head, body, tail or paws. Follow the product instructions and your veterinarian's recovery guidance.
Recovery wear
Compare the neck, chest and back measurements with the specific product chart. Recovery wear should provide coverage without restricting walking, breathing, toileting or normal movement.
Recovery products are not a replacement for veterinary advice. Contact your veterinarian if you are unsure whether a product provides suitable coverage for your pet's condition.
How to Use a Product Size Chart
Follow these steps each time you choose a product. Do not assume that the same size will fit across different designs.
Open the Product Chart
Find the size table and measurement notes on the individual product page.
Compare Every Relevant Measurement
Check neck, chest, length, height or internal dimensions depending on the product type.
Use Weight as Supporting Information
Weight can help narrow the options, but body measurements should determine whether the product is likely to fit.
Read the Product Notes
Check adjustment ranges, material flexibility, usable dimensions and any recommendations for pets between sizes.
Check the Fit Before Use
- Your pet can breathe and move normally
- No strap or opening presses tightly into the body
- The product does not slide or rotate excessively
- Buckles zippers and adjustment points are secure
- Your pet cannot easily back out or escape
- The product is used only for its intended purpose
- Your pet is supervised when first using the product
Size Guide Questions
Review these common questions before choosing your size.
Why can the same size differ between two products
Products may use different patterns, materials, adjustment systems and internal constructions. A size M in one design may have different measurements from a size M in another design.
Always use the measurements shown on the individual product page rather than selecting the same size automatically.
Can I choose a size using only my pet's weight
Weight should be used only as supporting guidance. Pets with the same weight can have different necks, chests, body lengths and heights.
Measure your pet and compare all relevant measurements with the product chart.
What should I do if my pet is between two sizes
Review the product's adjustment range, material flexibility and fit notes. The larger size may be more suitable for products that need additional room, but a larger harness may not be secure if it cannot be adjusted closely enough.
Contact us with the product link and your pet's measurements if you would like help reviewing the available information.
Should I allow extra room for thick fur
Yes. Measure over your pet's natural coat without compressing it tightly. Consider seasonal coat changes for long-haired or double-coated pets.
The product should remain comfortable without becoming loose enough to move excessively or allow escape.
Can HeyMyCat guarantee that a recommended size will fit
We can help you review the measurements and product information available, but every pet has a different body shape and individual comfort preference.
Final fit should always be checked by the pet parent before the product is used outdoors, during travel or throughout recovery.
What information should I send when asking for sizing help
Please send:
- The product name or product page link
- Your pet's species and breed when known
- Current body weight
- Relevant neck chest length and height measurements
- The size options you are considering
Submit this information through our Contact Us page .
Still Unsure About the Size
Send us the product link and your pet's relevant measurements. Our customer care team will help you review the available size information and typically replies within one business day from Monday to Friday.