Choosing the right size is one of the biggest decisions when buying a metal building. This guide covers width, length, height, and how to match size to use.
Size Matters More Than You Think One of the most common regrets we hear from metal building owners is: "I wish I had gone bigger." It's natural to size a building for your current needs, but a little extra space costs surprisingly little compared to the convenience it provides. Whether you're buying a carport, garage, workshop, barn, or commercial building, getting the dimensions right from the start saves you the cost and hassle of upgrading later. Width: How Wide Should Your Building Be? Width is typically the first dimension to determine because it's based directly on what you plan to store or shelter. Here are the standard width recommendations: 12' — Single vehicle (compact to mid-size car) 14' — Single vehicle with extra clearance (truck or SUV) 18' — Two compact cars or one vehicle plus workspace 20' — Two mid-size vehicles side by side 22' — Two full-size vehicles with comfortable door-opening clearance 24' — Two large vehicles (trucks, SUVs) with generous room 30' — Three vehicles or two vehicles plus dedicated workspace 40' — Four vehicles, large workshop, or agricultural equipment 50'+ — Commercial applications, large equipment, or multi-use buildings Length: How Long Should Your Building Be? Length is determined by the number and size of items you plan to store, plus the buffer space needed for comfortable access. Standard lengths start at 21 feet and increase in 5-foot increments (21', 26', 31', 36', 41', etc.). 21' — Standard car parking (about 2 feet of buffer front and back) 26' — Car plus small workshop area or storage at the back 31' — Large truck, SUV, or car with significant workspace 36' — Most boats, small to mid-size RVs 41' — Large RVs and motorhomes (measure your RV + add 5') 50'+ — Multiple bays, commercial use, or equipment lines Height: Don't Overlook Side Wall Height Side height is measured at the wall, not at the peak. This is a critical distinction because the peak height will be several feet taller depending on your roof style and building width. Common side heights and their uses: 6' — Minimum for standard cars (tight fit, limited to basic carports) 7' — Standard single garage door height 8' — Standard double garage door height with clearance 9' to 10' — Trucks, SUVs, lifted vehicles, most enclosed garages 12' — Large RVs, box trucks, agricultural equipment 14'+ — Tall RVs, commercial vehicles, equipment with lift attachments Sizing for Specific Uses Here are our most popular size recommendations by building type: Single Carport: 12'W x 21'L x 7'H — Basic car protection Double Carport: 20'W x 21'L x 7'H — Two-car coverage Single Garage: 14'W x 26'L x 9'H — One car, enclosed with storage Double Garage: 22'W x 26'L x 9'H — Two cars, fully enclosed Workshop: 24'W x 31'L x 10'H — Vehicle plus work area RV Cover: 18'W x 36'L x 12'H — Standard RV or large boat Barndominium: 30'W x 40'L x 12'H — Open concept living/working space Farm Building: 40'W x 60'L x 14'H — Large equipment and livestock Commercial: 50'W x 100'L x 16'H — Warehouse, manufacturing, retail The 'Go Bigger' Rule Our number one piece of advice: if you're debating between two sizes, go with the larger option. The incremental cost of an extra 5 feet of length or 2 feet of width is minimal compared to the total building cost, but the extra space is invaluable. You'll find uses for it — whether it's a workbench, tool storage, a second vehicle you didn't plan on, or simply the comfort of not squeezing past your car to get to the door. Get a Custom Quote Every property and every need is different. Our Building Specialists can help you determine the exact dimensions that work best for your situation. Call (833) 722-7678 for a free consultation, or design your building in 3D at Cardinal Carports.sensei3d.com to visualize different size options before you buy.