A wheelchair that is too narrow or too wide can cause discomfort. When too narrow, a wheelchair can become restrictive and increase the likelihood of pressure sores, while when it's too wide, becomes more difficult to push due to the angle of the arms from the shoulders to the wheels.

To determine the necessary seat width, measure the rider's widest area of the body and add one inch. This will allow for optimum seat width while maintaining ideal usability, comfort and safety.

To determine the appropriate seat depth, measure from the back of a chair to the inside of your knee. Subtract one inch to assure no contact is made between the edge of the wheelchair seat and the inside of your leg, which could cause discomfort and prevent the rider from sitting back fully in the chair.

Armrests are mostly a matter of personal choice, but most often users without much mobility appreciate armrests to help alleviate shoulder and back stress. Armrests also provide additional stability for users with limited upper body balance and are helpful when navigating in and out of the wheelchair. Additionally, armrests allow users the ability to do pushups, helping relieve pressure as well as protecting clothing from the wheels.

When armrests are not fitted properly the wheelchair can become more difficult to push. Not all armrests are adjustable. Height should be fitted to allow the forearm to rest fully on the armrest without pushing up on the shoulders. For users who sit at a table or desk, swing-away armrest can beneficial.

There are four basic types of armrests:
1. Full length, fixed height (entire armrest is padded with a non-adjustable height)

2. Full length, adjustable height (entire armrest is padded with various height seetings)

3. Desk length, fixed height (partial armrest is padded for easier access with tables, non-adjustable height)

4. Desk length, adjustable height (partial armrest is padded for easier access with tables, various height seetings)

Armrest that can be easily removed or flip up and down gives users the choice of when to use the armrests.