The short answer

Measure the vehicle in the same configuration in which you will use the liner. Third-row cargo space changes with seatback angle, split folding, sliding rails, storage wells, wheel wells, and hatch trim. A catalog width can be correct for the model family and still be wrong for a trim level or seat arrangement.

Record these dimensions

Dimension Where to measure Why it matters
Narrow floor width Between the closest trim or wheel-well points Controls the liner’s minimum width.
Maximum width Widest usable floor section Shows whether a molded edge can flare.
Depth Seatback to hatch threshold Prevents a liner from stopping short.
Height changes Wells, rails, and folded seat steps A flat liner may bridge or curl here.
Access clearances Latches, seat belts, and emergency release Protection cannot block operation.

Use a flexible tape, photograph the measurement with the seat position visible, and note whether the hatch closes without pressing the liner. Keep a record of the model year, body style, trim, and power-seat hardware. Do not pull on seat belts or remove trim to obtain a more exact number.

Judge fit after delivery

The liner should lie flat, avoid lifting the hatch seal, preserve seat movement, and keep tie-downs and release handles usable. A small edge gap can be preferable to a curled edge that catches cargo or stops the hatch from closing.

Limits

This is a measurement method, not a fitment guarantee. The vehicle manual and exact product application control when seat, belt, airbag, or hatch features are involved.