How to measure your car boot: the six measurements that matter

Updated 4 November 2026 · 7 min read

Most "will it fit?" questions can be answered with a tape measure and ten minutes. The trick is measuring the right things. A brochure's boot volume in litres won't tell you whether a 120 cm box will go in, but six straight-line measurements usually will. This guide covers each one: where to put the tape, what to watch for, and how to write the numbers down so you can use them in the car boot fit calculator.

Before you start

• Set the car up the way you'll load it. Take out loose items, boot organisers and the parcel shelf or load cover (or note that it stays in). If your car has an adjustable boot floor, decide which level you'll use and measure at that level.
• Note the seat positions. Seats-down length depends on where the front seats are, so note the driver's seat position you'll actually drive with.
• Measure the narrowest point, not the widest. Cars have curved trim, wheel arches and tapering openings. The smallest dimension along the path the item will take is the one that matters.

The six core measurements

A. Boot floor length (seats up)

Measure along the floor from the inside of the closed tailgate or boot lid to the back of the rear seats. Most people measure this wrong because the tailgate isn't there when the boot is open. Do one of these instead:

1. Measure from the back of the rear seatback (at floor level) to the inner edge of the boot opening, i.e. the inside face of the bumper or sill trim.
2. Close the boot gently, or look at where the closed tailgate's inner trim sits, and check whether it comes further in than the sill. Many tailgates have trim panels or a latch housing that stick inwards.
3. Record the shorter of the two numbers. If the seatback is reclined, measure at the height your item will sit at, not just at the floor.

B. Narrowest width (usually between the wheel arches)

In most cars the rear wheel arches intrude into the boot. That gap between the arches is often the narrowest point of the load floor, and it's the width a flat box has to pass between. Measure straight across between the innermost points of the arch trims, keeping the tape level. Our guide to wheel arch width explains when you can use the extra width higher up.

C. Usable height

Measure from the boot floor straight up to the lowest thing that would hit the top of your item. That's the parcel shelf if it stays in, the load cover, or the roof lining or tailgate trim if both are removed. Height is often lower at the back (where the tailgate slopes in) than near the seats, so measure in two places and use the lower figure for anything that spans the full length.

D. Opening width

With the boot fully open, measure the clear width of the opening between the side trims, seals or tail-light housings. Many openings are narrower at the top than at the bottom, so measure at the height where the widest part of your item will pass through. See how to measure a boot opening for the details.

E. Opening height

Measure from the top of the loading lip (the sill or bumper edge the item slides over) to the lowest point of the open tailgate or boot lid aperture. That might be a latch, a seal or a rubber stop. On saloons (sedans) this aperture is often far smaller than the space inside the boot.

F. Seats-down length

Fold the rear seats as you would for a long item. Measure from the inside of the closed tailgate (as in A) to the back of the front seats, at the height where your item will sit. The front seat backrest leans backwards, so the distance at floor level and at 40 cm up can differ by several centimetres. Note any step or gap where the folded seatback meets the boot floor. Our guide to folding rear seats covers uneven and sloping load floors.

Optional measurements that prevent surprises

The six numbers above cover rectangular boxes. If your item is tall, long or close to the limits, these extras are worth a couple of minutes:

A worked example

Here's a hypothetical hatchback with these measurements: floor length (A) 95 cm, width between arches (B) 100 cm, usable height without the parcel shelf (C) 70 cm, opening width (D) 95 cm, opening height (E) 65 cm and seats-down length (F) 160 cm. You want to carry a hypothetical box of 120 × 60 × 40 cm, with 2 cm of clearance on each dimension.

• Seats up: the box's longest side (120 cm) is longer than every interior dimension (95, 100 and 70 cm). It doesn't fit in any of the six orientations.
• Seats down: laid flat with 120 cm along the car, it needs 122 cm of length (160 available), 62 cm of width (100 available) and 42 cm of height (70 available). The interior is fine.
• Through the opening: slid in lengthways, the box presents a 60 × 40 cm end to the opening. That needs 62 × 42 cm, and the opening is 95 × 65 cm, so it passes.

Result: likely fits with the rear seats folded. If any number had come within a centimetre or two of its limit, the honest answer would be "might fit", and that's when a mock-up or a trial load is worth it.

Common measuring mistakes

• Measuring the widest point of the boot instead of the gap between the arches.
• Measuring length to the bumper with the tailgate open, ignoring the tailgate trim that sits inside when closed.
• Forgetting the parcel shelf, load cover or a raised boot floor.
• Measuring seats-down length at floor level when the item will sit higher, where the front seatback leans back into the space.
• Using the product's dimensions instead of the box dimensions.

There's a longer list with fixes in common car measuring mistakes.

Next steps

Write your six numbers down and keep them on your phone. You'll use them every time you buy something big. Put them into the car boot fit calculator, or check several items at once with the multiple items calculator. If you don't have the car to hand, our vehicle directory lists sourced boot measurements for some models. Measurements from your own car are still the most reliable.