Building your own shed can cost half as much as buying a kit, but only if you know your material quantities. The biggest cost drivers are the floor system, wall sheathing and siding, and the roof. Gable roofs add triangular end walls; lean-to (shed) roofs make one wall taller than the other.
How to use the DIY Shed Cost Calculator
- Shed length
- Shed width
- Wall height
- Roof style
- Roof pitch (rise per 12 run)
- Roof overhang
- Doors
- Windows
- Floor (joists, decking) price
- Foundation price (skids, gravel pad)
- Wall (framing, sheathing, siding) price
- Roof (framing, decking, shingles) price
- Price per door
- Price per window
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the footprint, wall height, roof style and pitch, overhang, the number of doors and windows, and local unit prices. The calculator works out each surface area and multiplies it by the price you set, then adds doors, windows and the foundation.
Good to know
Use the prices from your local lumber yard: a pressure-treated floor, OSB sheathing with T1-11 siding and asphalt shingles are the common budget choices.
Tips for an accurate estimate
- Sketch the job and split irregular areas into rectangles, circles and triangles before you measure.
- Add a waste allowance – typically 5–10% for simple layouts and 15–20% for diagonal, curved or heavily cut work.
- Check the coverage or yield printed on the product, because sizes and densities vary between manufacturers.
- Buy all units of a finished material (tile, brick, siding) from the same batch so colours match, and keep a few spares for repairs.
- Confirm local prices – quarry, lumber and steel prices vary widely by region and season.
Common mistakes to avoid
- Ordering exactly the calculated amount with no allowance for breakage, offcuts and settlement.
- Forgetting to subtract doors, windows and other openings – or subtracting small ones that still need cutting around.
- Confusing US short tons (2,000 lb) with metric tonnes (1,000 kg) when comparing quotes.
Inputs explained
| Field | What to enter |
|---|---|
| Shed length | Units: ft, m, in, yd, cm |
| Shed width | Units: ft, m, in, yd, cm |
| Wall height | Units: ft, m, in, yd, cm |
| Roof style | Choose one: Gable, Lean-to / shed (slopes across width), Hip |
| Roof pitch (rise per 12 run) | In /12 |
| Roof overhang | Units: in, cm, mm, ft, m |
| Doors | A number |
| Windows | A number |
| Floor (joists, decking) price | Units: /ft², /m², /yd² |
| Foundation price (skids, gravel pad) | Units: /ft², /m², /yd² |
| Wall (framing, sheathing, siding) price | Units: /ft², /m², /yd² |
| Roof (framing, decking, shingles) price | Units: /ft², /m², /yd² |
| Price per door | Units: /piece |
| Price per window | Units: /piece |
What each result means
- Floor area = [Shed length]×[Shed width]
- Roof area = ([Shed length] + 2×[Roof overhang])×([Shed width] + 2×[Roof overhang])×sqrt(1 + ([Roof pitch (rise per 12 run)]÷12)^2)
- Floor and foundation cost = [Floor area]×([Floor (joists, decking) price] + [Foundation price (skids, gravel pad)])
- Wall cost = [Wall area]×[Wall (framing, sheathing, siding) price]
- Roof cost = [Roof area]×[Roof (framing, decking, shingles) price]
- Doors and windows = [Doors]×[Price per door] + [Windows]×[Price per window]
- Total shed cost = [Floor and foundation cost] + [Wall cost] + [Roof cost] + [Doors and windows]
Example values
How the main result changes when Shed length changes and everything else stays at the example values above:
| Shed length (ft) | Total shed cost |
|---|---|
| 6 | 2,185.78 |
| 9 | 2,698.54 |
| 12 | 3,211.31 |
| 15 | 3,724.07 |
| 18 | 4,236.83 |
| 24 | 5,262.36 |
Formula
Floor = L × WWalls = 2 (L + W) × H + gable or lean-to extraRoof = (L + 2o)(W + 2o) × √(1 + slope²)Cost = Σ area × price + doors + windowsWorked example
Inputs — Shed length: 12 ft; Shed width: 8 ft; Wall height: 7 ft; Roof style: Gable; Roof pitch (rise per 12 run): 4 /12; Roof overhang: 6 in; Doors: 1; Windows: 2; Floor (joists, decking) price: $4 /ft²; Foundation price (skids, gravel pad): $1.5 /ft²; Wall (framing, sheathing, siding) price: $5 /ft²; Roof (framing, decking, shingles) price: $6 /ft²; Price per door: $250 /piece; Price per window: $120 /piece.
Results — Floor area = 96 ft²; Wall area = 290.7 ft²; Roof area = 123.3 ft²; Floor and foundation cost = $528.00; Wall cost = $1,453.33; Roof cost = $739.97; Doors and windows = $490.00; Total shed cost = $3,211.31.
Frequently asked questions
How much does it cost to build a shed yourself?
Materials typically run $15–$40 per ft² of floor area depending on finishes, so a 10 × 12 shed costs roughly $2,000–$5,000.
Is it cheaper to build or buy a shed?
Building usually saves 20–50% on materials versus a kit or prebuilt shed, but takes several weekends.
Do I need a permit?
Many areas exempt sheds under 120–200 ft²; check your local building department and HOA rules.
What formula does the DIY Shed Cost Calculator use?
Floor = L × W.