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Shed Construction Cost Calculator

Shed cost = floor area × floor rate + wall area × wall rate + roof area × roof rate + doors and windows. An 8 × 12 ft shed, 7 ft to the eaves with a 4 in 12 gable roof and 6 in overhangs, has 96 ft² of floor, about 264 ft² of wall after a 27 ft² door and window, and 123 ft² of roof. Enter your local rates for the total.

Inputs

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Shed
m
m
m
m
m²
Your rates (examples: use local prices)
/m²
/m²
/m²
Gable end of the shedShed 2,8552.4 m2.1 mmyconstructioncalculator.comNot to scale
Diagram updates as you type.

Results

Check the working before you order.

Estimated shed cost
2,855
Floor and foundation (8.6 m²)389
Walls (23.7 m²)1,306
Roof (11.2 m²)560
Doors, windows and fittings600
Cost per m² of floor330
Roof rise0.44 m
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Working
  1. Floor = 8.6 m²
  2. Rise = W ÷ 2 × tan 20.0°; walls = 2(W + L) × H + two gable triangles − openings = 23.7 m²
  3. Roof = 2 × (L + 2 × overhang) × (W ÷ 2 + overhang) ÷ cos pitch = 11.2 m²
  4. Floor and foundation: 8.64 m² × 45.00 = 389
  5. Walls: 23.75 m² × 55.00 = 1,306
  6. Roof: 11.21 m² × 50.00 = 560
  7. Total = 2,255 + 600 = 2,855
Results are estimates for planning and material ordering only. They are not a substitute for structural design or approval by a qualified engineer. Read the full disclaimer.
Formula


Floor = width × length
Rise  = (width ÷ 2) × tan(pitch) for a gable, width × tan(pitch) for a lean-to
Walls = 2(width + length) × eave height + gable or lean-to triangles − openings
Roof  = gable: 2 × (L + 2o) × (W ÷ 2 + o) ÷ cos(pitch)
Cost  = floor × rate + walls × rate + roof × rate + doors and windows


Worked Example


An 8 × 12 ft gable shed, 7 ft eaves, 4 in 12 pitch (18.4°), 6 in overhang, 27 ft² of door and window:


    

  1. Floor = 8 × 12 = 96 ft²
    2. 

  2. Rise = 4 × tan 18.4° = 1.33 ft; walls = 2 × 20 × 7 + 8 × 1.33 − 27 = 264 ft²
    3. 

  3. Roof = 2 × 13 × 4.5 ÷ cos 18.4° = 123 ft²
    4. 



Areas for Common Shed Sizes (7 ft eaves, 4 in 12 gable, 6 in overhang)






Shed
Floor
Walls (less 27 ft² of openings)
Roof






8 × 12 ft
96 ft²
264 ft²
123 ft²




10 × 12 ft
120 ft²
298 ft²
151 ft²




12 × 20 ft
240 ft²
445 ft²
288 ft²






Frequently Asked Questions
How do I work out the cost to build a shed?
Measure the floor, wall and roof areas, multiply each by a local rate per m² or ft² for materials and labour, and add doors, windows and fittings. Rates from a local builder or a supplier's price list give the most reliable answer.
How do I find the roof area of a shed?
For a gable roof: 2 × (length + 2 × overhang) × (half the width + overhang) ÷ cos(pitch). For a lean-to: (length + 2 × overhang) × (width + 2 × overhang) ÷ cos(pitch).
What roof pitch is 4 in 12?
A rise of 4 for every 12 across, which is 18.4°. 3 in 12 is 14.0°, 6 in 12 is 26.6° and 12 in 12 is 45°.
Gable or lean-to roof?
A lean-to is simpler and suits a shed against a wall or fence; a gable gives more head room down the middle and sheds rain both ways. The calculator handles both.
What foundation does a shed need?
Small timber sheds often sit on a timber frame on pavers or skids; larger or heavier sheds need a concrete slab, commonly 100 mm (4 in) thick on compacted gravel for a garden shed, and thicker for vehicles or heavy machines. The Slab Concrete Calculator works out the concrete.
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