Cat Flaps for a British Shorthair
Chunky build — may benefit from a large cat flap opening. A typical British Shorthair weighs 4.5–7 kg. Broad chests mean we measure shoulder width before choosing between a standard flap and a pet door.
Get a free quote for your British ShorthairWhat size opening does a British Shorthair need?
Standard 165 × 171 mm usually works, but we measure chest width first.
How to measure your British Shorthair
- 1Measure the chest at its widest point, behind the front legs, with the coat flat rather than fluffed up.
- 2Measure shoulder height from the floor and add 25–30 mm for a comfortable head clearance.
- 3Compare both figures against the standard 165 × 171 mm opening — if either is close, we step up to the 214 × 256 mm pet door.
- 4Check the belly height so the step-over isn't a hop for a heavy cat.
Where we fit it: We fit at around 130–150 mm off the floor. If the chest measurement lands within 15 mm of the standard opening, we'd rather move up to the larger pet door than have a tight squeeze every day.
Not sure? Try the Will It Fit checker.
Microchip compatibility for a British Shorthair
Every microchip flap we fit reads the standard 15-digit FDX-B chip used by UK vets and rescue centres, so your cat's existing chip works — no new chip and no collar tag needed. SureFlap models also read older 9 and 10-digit chips. If your cat isn't chipped, a collar-tag or manual flap is the alternative.
British Shorthair microchip tip
Chips can migrate down the shoulder on a heavy-set cat. If the flap hesitates, a vet can re-scan in seconds to confirm the chip's position.
Got the chip number handy? Check it against every flap we fit.
Getting a British Shorthair used to the cat flap
Prop the flap open for the first few days so your cat can see straight through, then let it down once they're using it happily. Treats on the far side and a calm house beat any amount of pushing.
Fitting note: Broad chests mean we measure shoulder width before choosing between a standard flap and a pet door.
Cat flaps we recommend for a British Shorthair
These are the models we fit most often for British Shorthairs, in order of preference.
SureFlap Microchip Cat Flap
Our default fit for average-sized cats — reliable chip reading and a 4-way manual lock.
- Opening 165 × 171 mm, cut-out 212 × 212 mm
- Reads all standard 15-digit FDX-B chips plus older 9 and 10-digit chips; stores up to 32 pets
SureFlap Microchip Pet Door
The large chip-reading door we fit for big cats and small dogs.
- Opening 214 × 256 mm, cut-out 256 × 300 mm
- Reads all standard 15-digit FDX-B chips; stores up to 32 pets
SureFlap DualScan Microchip Cat Flap
Best where one cat stays in and another goes out — perfect for multi-cat households.
- Opening 165 × 171 mm, cut-out 212 × 212 mm
- Reads all standard 15-digit FDX-B chips and sets in/out permissions per cat
Ready to give your British Shorthair the run of the garden?
We fit into uPVC, composite, wooden and aluminium doors, windows and new toughened glass panels.
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