Most popular home air compressors range from 5 to 10 gallons in size. Size isn't an ideal measurement on its own size CFM (air flow) is very important for choosing an air compressor and this will determine what tools the compressor can use. But if you have practical size and weight restrictions in your home or shop then you'll be best served with something over 2 gallons and under 10, with most people buying a 6-gallon pancake-style compressor.