Get a pet carrier size large enough that your pet has room to turn around and stretch out to relax. You will also need to get a carrier built to hold your pet’s weight. Measure your pet’s back length and add a few inches to it to get an ideal carrier length. Then, add 2-3 inches to your pet’s shoulder height to calculate the right height for a soft-side carrier, or add 3-5 inches for a hard-sided carrier. Wearable carriers like slings can be more compact than travel carriers, so look for one with a snug, cozy fit that still leaves some room to move.