What this calculator does
A shed cost calculator turns a floor size and a price per square metre into a rough materials estimate, before a single quote has come in. It will not replace a builder or kit supplier quote, since sheds range from a flat-pack kit to a fully custom-built structure, but it gives a starting figure to plan a budget against.
The biggest source of error in any shed estimate is treating one number as universal. Materials price per square metre varies enormously by shed type (timber-frame, steel kit, colorbond) and region, so every price here is a field you set from your own quotes or supplier catalogue, never a figure baked into the tool.
The formula
Floor area is length multiplied by width. That area is then multiplied by the materials price per square metre, plus an optional slab price and an optional roofing price per square metre if those are quoted separately, and a flat allowance for extras such as delivery, permits or fittings is added on top.
| Term | Meaning |
|---|---|
| Floor area | Shed length × width, in square metres. |
| Materials price per m² | What the shed structure itself costs per square metre of floor area, from a supplier quote or kit price. |
| Slab price per m² | The cost of a concrete base, if one is being poured, set to 0 if the shed sits on an existing surface or footings only. |
| Flat extras | One-off costs that do not scale with floor area, such as delivery, council permits or door and window fittings. |
The inputs explained
| Field | What to enter |
|---|---|
| Shed length (m) | The shed footprint length. |
| Shed width (m) | The shed footprint width. |
| Materials price per m² of floor area ($) | The materials price per m² for the shed structure, from a quote or kit listing. |
| Concrete slab price per m² (0 if not needed) ($) | The concrete slab price per m², or 0 if no slab is being poured. |
| Roofing price per m² (0 if included in materials price) ($) | A separate roofing price per m², or 0 if roofing is already included in the materials price. |
| Flat extra costs (delivery, permits, fittings) ($) | A flat amount for delivery, permits, fittings or anything else that does not scale with floor area. |
When to use it
Budgeting before getting quotes
Entering a rough materials price from a catalogue or a similar project gives a starting budget figure to compare real quotes against once they arrive.
Comparing a kit shed against a custom build
Kit sheds and custom timber builds usually quote very different prices per square metre; running both through the same formula puts them on the same footing.
Deciding whether a slab is worth it
Setting the slab price to 0 versus a real quoted figure shows exactly how much of the total cost a concrete base adds, before committing to one.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the total cost changes with floor area at a fixed price per m²
A fixed combined rate of $245/m² materials and slab, plus $200 in flat extras, across a range of shed sizes.
| Shed length (width fixed at 2.4 m) | Estimated total cost | Floor area | Effective cost per m² including extras |
|---|---|---|---|
| 2.4 m | $1,611.20 | 5.76 m² | $279.72 |
| 3 m | $1,964.00 | 7.20 m² | $272.78 |
| 3.6 m | $2,316.80 | 8.64 m² | $268.15 |
| 4.8 m | $3,022.40 | 11.52 m² | $262.36 |
| 6 m | $3,728.00 | 14.40 m² | $258.89 |
| 7.2 m | $4,433.60 | 17.28 m² | $256.57 |
How the total cost changes with materials price at a fixed floor size
A fixed 7.2 m² footprint, across a range of materials prices per m².
| Materials price per m² | Estimated total cost | Materials, slab and roofing subtotal |
|---|---|---|
| $100 | $1,388.00 | $1,188.00 |
| $150 | $1,748.00 | $1,548.00 |
| $180 | $1,964.00 | $1,764.00 |
| $220 | $2,252.00 | $2,052.00 |
| $280 | $2,684.00 | $2,484.00 |
| $350 | $3,188.00 | $2,988.00 |
Questions
Why is there no default "typical shed cost" figure?
Shed costs vary hugely by construction type, size, material and region, from a small flat-pack kit to a fully custom timber build, so any single quoted figure would be misleading. Enter a price from your own quote, kit listing or supplier catalogue instead.
What if roofing is already included in the materials price?
Leave the roofing price at 0. Many kit and pre-fabricated shed quotes already bundle roofing into a single materials price per m², so adding a separate figure would double-count it.
Does this include labour?
Only if you fold a labour rate into the materials price per m² yourself, or add it as a flat extra. A DIY build with no paid labour and a kit or trade-supplied build with installation included will have very different figures for the same shed size.
Should council permit fees go in extras?
Yes, if you know the fee, add it to the flat extras field alongside delivery and fittings costs, since none of those scale with the size of the shed.
For a similar area-based materials estimate with underlay and installation built in, see the carpet quote calculator. For a paving job around or leading up to the shed, see the paving cost estimate calculator.