Measuring your rabbit accurately is an important step in ensuring that you choose a harness that is the right size, and one that isn’t simply going to slip off. You will need a flexible tape measure that you can comfortably wrap around them. Measure carefully across their breast area towards one finger width behind their front leg. Your rabbit should be sitting during all this rather than laying on the ground. Next, you will need to measure the circumference of their belly area. You will also need to take a neck measurement.\r