What is the smallest practical shed size?

8×10 feet (80 sq ft) is the smallest shed most sizing guides treat as a true walk-in: a push mower in one corner, a tool rack along the wall, and still room to turn around. Guides class 8×8 to 8×12 as "small" and call 8×10 the standard that fits most yards. This tool floors every equipment calculation at 80 sq ft — if your gear math says 64 sq ft, it still recommends an 8×10, because a smaller shed gets cramped fast.

What size shed do I need for a riding mower?

A typical 42-inch-deck riding mower is about 53×73 inches (3,869 sq in = 26.87 sq ft). With the tool's 25% access-and-growth allowance that is 33.59 sq ft of planning area, so an 8×10 (80 sq ft) is the honest minimum — but once you add tools and a workbench, a 10×12 is the comfortable pick most owners land on. Plan a 60-inch double door: the 53-inch mower plus 6 inches of maneuvering needs a 59-inch opening, and 60 inches is the nearest stock door size.

How much bigger than my equipment should the shed be?

Add about 25% on top of your equipment's bare footprint for access and growth, then round up to the next stock size — and when in doubt, buy one size bigger than you think you need. Example: gear totalling 96 sq ft × 1.25 = 120 sq ft, which lands exactly on a 10×12. The tool applies this factor automatically, with 8×10 as the floor.

How wide should my shed door be?

Stock shed doors run 30 and 36 inches single, and 48, 60, 72 inches double. The planning rule: the clear opening should be at least the widest item plus 6 inches of maneuvering room. A push mower (24 in wide) needs 30 inches, so a 30-inch single door works. An ATV (48 in) needs 54 inches, so step up to 60-inch double doors. Anything wider than a 72-inch opening usually means sliding or roll-up doors instead of hinged ones.

How deep should a gravel pad be, and how far past the shed?

Use 4 inches of compacted crushed stone (the published range is 4–6 inches; never pea gravel — it shifts). Extend the pad 12 inches past the shed on every side so roof runoff lands on gravel, not soil. For a 10×12 shed that is a 12×14 ft pad = 168 sq ft, needing 56 cubic feet = 2.07 cubic yards of stone — about 3.11 tons at 1.5 tons per cubic yard, or 112 half-cubic-foot retail bags.

Concrete slab or gravel pad for a shed?

Gravel is the most common choice: cheap, DIY-friendly, and drains well — roughly $300–$800 DIY for the pad and timber frame. A 4-inch concrete slab for a 10×12 shed needs 40 cubic feet = 1.48 cubic yards of concrete (about 67 eighty-pound bags if you mix it yourself), and a pro-installed slab typically runs $1,500–$3,000. Slabs are more permanent and stable; gravel is easier to level, cheaper, and simpler to remove later.

Do I need a permit to build a shed?

Often not for small sheds — but it depends on your city. The most common US local threshold is 120 sq ft: one-story detached sheds at or under 120 sq ft (exactly a 10×12) are exempt in many jurisdictions, while larger ones commonly need a building permit. Three common triggers even under 120 sq ft: utilities (electric/plumbing), height over 12 ft, and sitting closer than 3 ft to the property line. The tool's permit mode checks all four against your inputs — then confirm with your local building department, because local rules always win.

How much does a shed cost in 2026?

Typical 2026 US ranges: an 8×10 runs $1,500–$3,000 DIY, $3,000–$6,000 as a kit, $5,000–$10,000 contractor-built, or $500–$2,000 as a resin/metal prefab. A 10×12 is $3,000–$5,000 DIY or $5,000–$8,000 as a kit; 12×16 is $4,000–$8,000 DIY or $7,000–$12,000 kit; 12×20 is $6,000–$12,000 DIY or $10,000–$18,000 kit. Add the foundation: an installed gravel pad runs about $320–$800 for 8×10 and $480–$1,200 for 10×12. Prices vary by region — treat these as planning budgets.

What fits in a 10×12 shed?

A 10×12 (120 sq ft) is the classic "workshop + storage" size. Example load: riding mower 26.87 sq ft + wheelbarrow 10.83 sq ft + wall tool rack 6 sq ft + workbench 10 sq ft = 53.70 sq ft of gear, or 67.13 with the 25% access factor — well under 120, leaving a proper 36-inch walkway and room to grow. It also sits exactly on the 120 sq ft permit threshold most US jurisdictions use.

What are common shed sizes in metric?

An 8×10 ft shed is 2.44 × 3.05 m = 7.43 m²; a 10×12 ft shed is 3.05 × 3.66 m = 11.15 m². Convert with: feet × 0.3048 = meters, square feet × 0.09290304 = square meters, inches × 2.54 = centimeters. The tool's footer shows metric equivalents for every result.

Shed Size Calculator — Equipment Sizer, Doors, Foundation & Permits

Equipment Sizer

Check everything you plan to store. The tool sums the footprints, adds 25% for access and growth, floors the result at the 8×10 minimum, and recommends the smallest stock size that fits.

Standard Shed Sizes

The stock sizes manufacturers actually sell, what each one is good for, and where it sits against the common 120 sq ft permit line.

Size (ft)	Area	Typical use	Permit
8x8	64	Small garden storage — hand tools, pots, bags	≤120 line
8x10	80	The standard backyard shed — push/riding mower + tools	≤120 line
8x12	96	Garden gear + push mower + a couple of bikes	≤120 line
10x10	100	Medium storage — mower, bikes, totes	≤120 line
10x12	120	Workshop + storage — sits exactly on the 120 sq ft permit line	≤120 line
12x12	144	Riding mower + gear with elbow room	permit zone
10x16	160	Riding mower + workbench + shelving	permit zone
12x16	192	Full workshop or office conversion	permit zone
12x20	240	Tractor + equipment storage	permit zone
12x24	288	Tractor + ATV + workbench	permit zone
16x20	320	Large workshop — car-sized storage	permit zone
16x24	384	Largest common stock size	permit zone

The 120 sq ft line is the exemption ceiling most US local codes use — a 10×12 sits exactly on it. Always verify with your local building department.

Walkway & Layout Check

Items stored along one wall eat into the width. A usable shed keeps a 36-inch clear aisle — this checks whether yours does.

Shed width (ft)

Deepest item along the wall (in)

Door Clearance Checker

The clear opening should be at least your widest item + 6 inches of maneuvering room. Pick the item (or enter a custom width) and your door opening.

Widest item

Door opening (in)

Foundation Estimator

Gravel pad is the default: 4" of compacted crushed stone, pad extending 12" past the shed on every side. Compare against a concrete slab and deck blocks.

Shed length (ft)

Shed width (ft)

Pad overhang each side (in)

Gravel depth (in)

Stone density (tons/yd³)

Permit & Setback Checker

Checks the four most common US local triggers — the 120 sq ft size line, the 12 ft height line, the 3 ft setback line, and utilities. Common thresholds, not your local code.

Shed length (ft)

Shed width (ft)

Shed height (ft)

Distance to property line (ft)

Adding electrical, plumbing, or mechanical

Cost Estimator

2026 US typical ranges for four anchored sizes, four build methods, plus the foundation — combined into a project budget.

Shed size

Build method

Foundation

Shed Sizing FAQs

Related tools

Gravel Calculator

Project material estimator — gravel, stone, and aggregate quantities for driveways and landscaping. Use it when the shed pad is only part of a bigger yard project.

Cubic Yards to Tons Calculator

Generic volume↔weight converter — convert any bulk material volume to weight. The shed tool already does this for stone; this one covers everything else.

Concrete Calculator

Concrete volumes and bag counts — slabs, footings, and piers beyond shed foundations.

Sourcing: the 8×10 minimum, size-to-purpose mapping, and 2026 cost ranges come from published shed-buying guides (Cool Sheds, Patiowell, Hammer & co.). The 53"×73" riding-mower footprint matches published spec sheets for 42-inch-deck machines (Cub Cadet XT1 52.0"×67.8", John Deere Z320R 50.4"×77.8", EGO TR4204 53"×73"). Gravel-pad rules (4–6" compacted crushed stone, 12" overhang) converge across foundation guides; the 120 sq ft / 12 ft / 3 ft permit thresholds are compiled from published municipal codes (Council Bluffs IA, Clovis CA, Anderson CA, Wellington CO, Wall NJ). Measure your own equipment and confirm permits locally — this tool is an educational estimator, not a building-code authority.

Shed Size Calculator

Equipment Sizer

Standard Shed Sizes

Walkway & Layout Check

Door Clearance Checker

Foundation Estimator

Permit & Setback Checker

Cost Estimator

Shed Sizing FAQs

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