Measuring a car boot for a dog crate

Begin with the dog

Measure the dog's standing length and height, body width and relaxed lying position, then compare them with the crate's usable internal room. An external dimension tells you whether a box might fit the car, not whether the dog can stand, turn and rest in it. Refer to the exact maker's dog-sizing guidance, especially where a crash-tested design has a defined size range.

Take the boot measurements in this order

The hatch aperture

Open the tailgate fully. Measure the narrowest width between trim pieces and the lowest usable height beneath hinges, handles or interior panels. Include the loading lip. The assembled crate must pass through this opening without forcing; a folding product may pass in parts but still need to be assembled and anchored as instructed.

The usable floor

Measure depth from the rear seat or seatback to the inside of the closed tailgate, then width between wheel arches and other protrusions. Note whether the floor is level, whether a false floor moves, and where cargo loops sit. Do not count space behind a loose parcel shelf or under a moving seat.

The slope and roof line

At the likely crate roof height, repeat the depth measurement. In many hatchbacks the upper depth is much shorter than the floor depth. A sloping crate may follow that contour, but its internal headroom must still fit the dog. Measure the closed hatch carefully; do not let glass or trim become the back stop for the crate.

The door and installation envelope

Allow space for the main door to swing or slide, hands to operate the latch, and any specified rear escape route. Find the vehicle's approved cargo points. Record the exact manufacturer's installation envelope: built-in geometry and additional clearance are not the same thing. Thule describes Allax's crumple zone as built into the design and specifies a tension-band installation. Do not add a universal rear gap or automatically count a built-in allowance twice. Use the chosen model's installation diagram; other products may differ.

Annotated car-boot clearance diagrams

The two views separate getting the crate into the car from accommodating it once installed. They are planning schematics, not a scale drawing of a particular vehicle. Letters match the worksheet below. There is no universal number for door, anchor or rear clearance: use the exact crate instructions.

Your car-boot fit-planning worksheet

Copy these fields into your notes, or print the guide. Record all measurements in centimetres and preserve the same seat and boot-floor configuration throughout. Include handles, feet, latches and other projections in the candidate's outside profile. Where the supplier's measurement boundary is unclear, resolve it before treating the number as available clearance.

For a sloping boot or crate, record additional widths and depths wherever the outline changes. A single roof-height reading cannot prove that every intermediate point clears. The internal versus external dimensions guide helps separate this vehicle envelope from the space your dog actually occupies.

Worked example: a floor fit can still fail higher up

All figures in this example are invented to explain the calculation. They do not describe the Thule or CADOCA products, an actual vehicle, or a recommended gap. Imagine a rectangular crate body 84cm deep, 60cm wide and 60cm high, and the available spaces shown below.

The calculation is available dimension − required dimension. The floor leaves 11cm on paper, but the boot is only 78cm deep at the crate's roof height: the 84cm rectangular body is 6cm too deep there. Positive hatch figures do not prove the loading manoeuvre works, and a numerical remainder is not all spare space to use; approved anchoring and model-specific allowances can consume it.

An angled candidate needs its actual side profile compared with the closed boot profile instead. Do not trim a crate, compress the car's lining or reduce dog space to make a calculation look favourable.

Check the planned outline before ordering

Make a cardboard outline using the candidate's full external width, height, depth and slope, including handles or catches. With the car parked securely, take the outline through the hatch and compare it with the proposed installed position and closed-tailgate profile. Keep hands clear and stop if anything contacts the hatch; never force it. Repeat at the door-open position. If the outline works only when tilted sharply, confirm the real crate can be introduced that way without damage. A lightweight outline cannot verify the crate's actual mounting or restraint performance.

A compact CADOCA illustrates why a smaller published exterior is only a starting point: its angled body may fit the boot, yet the dog still needs adequate interior length and height. Check exact listing dimensions and the permitted way to secure it.

Record the measurements and seat position you used. If you change vehicles, remove a boot floor or move the rear seats, measure again before travelling. Finish with the car-crate installation checklist.