A shed size calculator helps you determine the minimum and recommended shed square footage based on what you plan to store. Select your intended use and equipment below to get specific shed dimensions.
What Will You Store?
Check all items you plan to store. The calculator will total the required floor space plus a circulation allowance.
Standard Shed Sizes That Fit
How to Choose the Right Shed Size
Choosing a shed that's too small is the most common shed-buying mistake. Most people underestimate how quickly a shed fills up, and a cramped shed makes retrieving anything at the back an ordeal.
Step 1: Inventory What You're Storing
Check every item you plan to store. The calculator assigns footprints based on typical dimensions for each item type, plus a circulation allowance so you can actually move around inside the shed.
Step 2: Add 20-30% for Growth
Sheds tend to fill up faster than expected. If your calculated minimum is 100 sq ft, seriously consider a 120-140 sq ft shed. The incremental cost between adjacent sizes is usually small ($200-500) but the difference in usability is significant.
Step 3: Check Permit Requirements
Most local jurisdictions require a building permit for sheds over 120-200 sq ft. Sheds under 120 sq ft (roughly 10x12) are commonly exempt. Check your city's zoning department and HOA rules before purchasing — some HOAs prohibit visible sheds entirely.
Step 4: Consider Door Width
Standard shed doors are 60-72 inches wide. If storing a riding mower, you need at least a 6-foot-wide door. Double shed doors (two 36" panels) solve this problem. Measure your largest item's width and add 12 inches of clearance when choosing door configuration.
FAQ
Is this shed size calculator free?
Yes, completely free with no signup required. All recommendations are based on typical equipment dimensions and expert storage guidelines.
What size shed do I need for a riding lawn mower?
A riding mower typically needs at least 8x10 feet (80 sq ft) for the mower plus a small work area. If you also need space for hand tools, fertilizer, and garden equipment, step up to a 10x12 (120 sq ft) or 10x16 (160 sq ft) shed. Factor in turning radius — most riding mowers need a 5-6 foot turning radius to maneuver.
What is the most popular shed size?
The most popular residential shed sizes are 8x10 (basic storage), 10x12 (general purpose), and 12x16 (large storage or workshop). An 8x8 is the minimum practical shed — smaller sizes feel cramped once filled with equipment. A 10x12 is the sweet spot for most homeowners.
Do I need a permit for a shed?
Most jurisdictions require a permit for sheds over 120-200 sq ft (regulations vary by city/county). Many areas exempt sheds under 120 sq ft (roughly 10x12) from permits. Always check your local zoning ordinance and HOA rules before building — setback requirements from property lines also vary.
What size shed do I need for a full workshop?
A functional workshop needs at least 12x16 (192 sq ft) and ideally 12x20 to 16x20 (240-320 sq ft). This allows a workbench along one wall, tool storage on another wall, and a central work area for projects. Add extra space for any large tools like table saws, drill presses, or wood lathes.