Seat depth. Measure from the front of the seat upholstery to the back of seat upholstery. When sat in the wheelchair, you should have approximately 2-3 fingers between the front of the seat canvas and the back of the knee.
Backrest height. Measured from the bottom of the backrest post to the top of the backrest canvas. Backrest height depends on the degree of disability and level of support required.
Rear seat to floor height. Measure from the rear edge of the seat canvas straight down to the floor. By having a lower rear seat height to front seat height gives the chair 'seat bucket' meaning a sloping seat towards the rear.
Front seat to floor height. Measure from the front edge of the seat canvas straight down to the floor.
Frame/hanger angle. Depending on the wheelchair, various front frame angles are sometimes offered. This is usually measured from the seat frame so a 90 degree frame angle would make the front frame vertical. For example, a 70 degree front frame angle can help if the user's has long legs or trouble bending the knee.
Centre of gravity. Measure from the backrest post to the centre of the rear wheel axle. The larger the measurement, the more 'tippy' the wheelchair will be. The more 'tippy' the chair, the easier to turn on the spot and quicker to maneuver but better balance is required as more likely for the chair to tip backwards especially if not using anti-tipping aids.
Seat width. Measure from the outside to the outside of the seat frame tubes across the width of the seat. This should be measured across the user's widest point (usually the hips) allowing a small gap either side.
Footplate to seat canvas. Also known as 'knee to heel length'. Measure from the front edge of the seat canvas to the rear of the footplate. This can be measured from the back of the user's knee to the bottom of the sole of the shoe.
Rear wheel camber. This is the degree of angle on the rear wheels. If the wheels are vertical, the camber would be 0 degrees. Camber increases the ease of turning the wheelchair and lateral stability. However, camber also increases the overall width of the wheelchair. As a rough guide, 2 degrees of camber increases the overall width by 1 inch.