What size collar for a French Bulldog?
French Bulldogs typically need a small to medium collar, but because the breed's neck shape is short and often quite broad relative to its size, measuring your own dog's neck properly is far more reliable than relying on a general size chart for the breed. The method below takes a couple of minutes and avoids the most common sizing mistake, which is buying a collar based on the dog's overall size rather than its actual neck measurement.
How to measure your Frenchie's neck
Use a soft fabric tape measure, or a piece of string measured against a ruler afterwards, and wrap it around the middle of your dog's neck, where a collar would naturally sit. Slide two fingers flat underneath the tape as you measure, since this leaves enough room for a comfortable, correctly fitted collar rather than one that is too tight.
Measure with your dog standing normally rather than straining or pulling, since a neck measurement taken while a dog is tense or stretching can come out smaller than its relaxed, natural size. Taking the measurement twice and using the higher of the two readings is a sensible way to avoid ending up with a collar that is slightly too snug.
Why French Bulldogs are trickier to size than average
The breed's short, broad neck and relatively loose skin around that area mean a collar sized purely by the dog's overall weight or general breed averages can end up either loose enough to slip over the head or tight enough to rub, without the fit actually matching this particular dog's proportions.
Adult French Bulldogs commonly fall somewhere in the region of 25 to 40cm in neck circumference, but this range is wide enough that a measurement is genuinely necessary rather than optional — a small, narrow-necked Frenchie and a stockier one of similar weight can need noticeably different collar sizes.
Getting the fit right once you have a size
Once you have a measurement, check it against the specific manufacturer's size chart for the collar you are buying rather than assuming sizing is standard across brands, since 'small' and 'medium' vary meaningfully between manufacturers. If your dog's measurement falls between two sizes, sizing up and adjusting the buckle tighter is usually safer than sizing down and hoping it stretches.
Recheck the fit periodically, particularly for a young or still-growing French Bulldog, since a collar that fitted well a few months ago can become too tight as a puppy fills out, or too loose if a dog loses weight.
The sizes we stock
Everything below is in stock with us, priced with delivery worked out, and packed and posted by hand in the UK.
Real-Time GPS Pet Tracker
A compact GPS tracker that clips to most collars for real-time location, geofence alerts and find-me sound.
£29.99
Smart Bluetooth Tracker Tag (Works with Find My)
A compact Bluetooth tracker that pairs with Apple Find My for global positioning, with left-behind alerts and the option to share tracking with up to six people. Clip it to a pet collar, keys or bag so nothing goes missing.
From£7.99
Flea & Tick Repellent Collar for Dogs & Cats
An adjustable 70cm repellent collar, water-resistant and trimmed to fit either a cat or a dog, giving day-to-day deterrence against fleas and ticks with no drops to apply.
£7.99
Common questions
- What is the average neck size for a French Bulldog?
- Adult French Bulldogs commonly fall somewhere in the region of 25 to 40cm in neck circumference, but this range is wide enough that measuring your own dog properly matters more than relying on an average figure.
- How many fingers of space should fit under a Frenchie's collar?
- Two fingers, flat, slid comfortably underneath the collar while it is fastened, is the standard guide for a correctly fitted collar. Any tighter risks rubbing or restricting breathing, and any looser risks the collar slipping over the head.
- Should I buy a harness instead of a collar for a French Bulldog?
- Many owners of flat-faced breeds like French Bulldogs prefer a well-fitted harness for walking, since it avoids pressure on the throat and airway, which can be more of a concern for this breed than for a longer-nosed dog. A collar is still useful for holding an ID tag even if a harness is used for walks.
- How often should I recheck my French Bulldog's collar size?
- Check the fit every few weeks while your dog is still a growing puppy, since a collar can become too tight surprisingly quickly during a growth spurt. For an adult dog, rechecking every few months, or after any noticeable weight change, is a sensible habit.
- Why does my French Bulldog's collar keep slipping over its head?
- This usually means the collar is either sized too loosely for the dog's neck, or the neck itself is on the narrower end for the breed relative to the head size, which is common in some French Bulldogs. Remeasuring and trying a size down, checked against the two-finger rule, usually resolves it.
Sources
Written against guidance published by UK veterinary and welfare organisations. Always confirm specifics with your own vet.
Written by Matt Garnett, who runs Giddy Pets and is a lifelong pet owner — not a vet. This is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your animal. How we write these guides.