A good clothing size starts with measurements, not a breed label or the letter printed on an old garment. For a very small dog, even an inch can change how a neckline, sleeve or four-leg onesie sits—so it is worth spending two calm minutes with a soft tape measure.
The short answer
Chest girth is usually the first measurement to match. Then use back length to choose the closest overall fit. Weight is a useful cross-check, not the deciding number.
What you need
- A soft tailor’s tape—or a piece of string and a ruler
- A few small treats
- Your dog standing naturally on all four paws
- The size chart from the exact product you want
1. Measure chest girth first
Wrap the tape around the widest part of the rib cage, usually just behind the front legs. Keep it level around the body and close to the coat without squeezing. You should be able to slide two fingers comfortably beneath it.
Chest comes first because a garment that is too tight here can restrict normal movement, pull at the armholes and make dressing uncomfortable. If your dog’s chest sits near the maximum for a size, choose the next size unless the product page gives different guidance.
2. Measure back length
Place the tape at the base of the neck, where a collar naturally rests, and measure along the spine to the base of the tail. Your dog should be standing—not sitting, stretching or curling.
Back length helps prevent a garment from ending too early or bunching over the hips. If chest and back point to different sizes, protect comfortable chest room first and then look for the cut whose back length is closest.
3. Measure the neck when the product lists it
Measure around the lower neck where the garment’s neckline will sit. Do not pull the tape tightly. Neck measurement is especially useful for higher collars, sweaters and garments that pull over the head.
4. Use weight as a sense-check
For a tiny dog, weigh yourself, then weigh yourself while holding the dog and subtract. A kitchen or pet scale can be more precise for very low weights. Weight can flag an unusual result, but two dogs of the same weight can have very different chests and backs.
There is no universal Yikeyo size chart
Fabric stretch, garment construction and coverage change from one product to another. A size marked S in lightweight pajamas may not measure exactly like S in fleece or a recovery suit. Measure once, save the numbers in your phone, and compare them with the chart on each product page.
What if your dog is between sizes?
Choose the larger size when the smaller option would be snug through the chest. If the chest fits both sizes comfortably, use back length and the product’s stretch to break the tie. Our between-sizes guide walks through broad chests, long bodies, fluffy coats and different fabrics.
Check the fit in motion
- Confirm two-finger room at the neck and chest.
- Make sure armholes do not press into the armpits.
- Check that cuffs stay above the paws.
- Let your dog walk, turn, sit and lie down.
- Remove the garment if it changes their gait, causes panting or prompts persistent chewing.
Frequently asked questions
Which measurement matters most?
Chest girth usually comes first because the garment needs enough room for comfortable breathing and movement.
Should I measure over a fluffy coat?
Yes. Let the tape rest over the natural coat without crushing it, so the finished garment leaves realistic room.
Can I order by breed or weight?
Use those only as clues. Individual proportions vary too much for either to replace chest and back measurements.
Save the measurements in your phone, then compare them with the chart on the piece you like.
Shop all pet clothing