Construction calculators by trade and country
Published · By Sai Nath
Pick your trade or your country. Each page puts the calculators that job uses in one place: free web calculators, worked examples in that trade’s units, the mistakes that cost a re-do, and the building rules where you work, linked to the official source. For every calculator on one page, see all the construction calculators.
MeisterCalc is a construction calculator app for Android with 16 calculators, metric first, with feet and inches in Settings. The pages below sort those calculators, and the free web calculators on this site, by who uses them. They are written from the app’s own formulas and from the codes each country publishes, and each one works its own examples, so a stair builder, a concreter and a homeowner each get the numbers for their job.
Which calculators does each trade use?
Six trades, each with the calculators they reach for most and the jobs worked through on the page.
- Carpenters and chippies
Squaring a frame by its diagonals, studs and battens marked from one end, raked wall studs, pitch and triangles.
- Stair builders
Risers and goings from a floor-to-floor height, a stair that has to fit a fixed run, the stairwell opening and balusters on the rake.
- Deck builders
One deck carried through every step: set out square, footings, joists, boards and the gap, deck stairs and the balustrade.
- Concreters
Slab and pier volumes with an order allowance, bags from the maker’s yield, falls to a drain and base course to tonnes.
- Roofers
Pitch in degrees, X in 12 and per cent, the rafter line with its overhang, ridge height from the span and gutter fall.
- DIY builders
Small jobs in plain words: a garden bed, a gravel path, a small slab, even fence posts and a few garden steps.
Which rules apply where you build?
The maths is the same everywhere. The limits, the units and the names of the materials are not, so each country has its own page with its own examples.
- Australia
Millimetres, the NCC Housing Provisions for stairs, barriers and gutters, AS 1684 for timber framing, concrete in cubic metres and 20 kg bags.
- New Zealand
The NZ Building Code’s Acceptable Solutions (D1/AS1 for stairs, F4/AS1 for barriers) and NZS 3604 for timber framing and decks.
- United Kingdom
Approved Document K for stairs and guarding in England, stud spacing from the board maker or the structural design, and materials by the tonne and the bag.
- United States
Feet, inches and sixteenths, the IRC as your state or city adopts it, and concrete in cubic yards and bags.
- India
Rooms in feet and structure in millimetres, sand and aggregate in cft and brass, cement in 50 kg bags, bricks to IS 1077 and nominal mixes from IS 456.
How does one stair change from country to country?
Take one floor-to-floor height, 2700 mm, and build the shortest straight flight each country’s figures allow: the fewest risers that keep each riser under the maximum, then the smallest going the rules accept. The riser count comes from rounding up: risers = ⌈2700 ÷ maximum riser⌉, and run = treads × going, with one tread fewer than risers.
| Where, and the limits that decide | Risers | Going | Run |
|---|---|---|---|
| Australia, NCC 2025: riser 190 mm or less, going 240 mm or more | 15 × 180.0 mm | 240 mm (2R + G = 600) | 14 × 240 = 3360 mm |
| New Zealand, D1/AS1 main private stair: riser 190 mm or less, going 280 mm or more | 15 × 180.0 mm | 280 mm (pitch 32.7°) | 14 × 280 = 3920 mm |
| England, Approved Document K private stair: riser 220 mm or less, pitch 42° or less | 13 × 207.7 mm | 231 mm (pitch 41.96°) | 12 × 231 = 2772 mm |
| United States, IRC: riser 7 3/4" or less, tread 10" or more | 14 × 192.9 mm (7 9/16") | 254 mm (10") | 13 × 254 = 3302 mm (10′ 10") |
Same floor, four different stairs: the English flight is 1148 mm shorter than the New Zealand one because England allows a 220 mm riser and a 42° pitch, while New Zealand’s main private stair needs a 280 mm going. In England the 220 mm going minimum alone would give a 43.4° pitch, so the pitch limit sets the going there. These are the tightest flights the figures allow, not designs to build: most stairs are made easier than the minimum, and each table has notes and exceptions. The figures and their sources are in stair rules by country; the council, certifier or building department decides what applies to your stair.
Try your own height in the free stair calculator: it checks the result against all four.
Which of these calculators are in the MeisterCalc app?
All 16 are: Stairs, Baluster Spacing, Check Square, Pitch, Decking, Equal Spacings, Running Measurements, Raked Walls, Triangles, Concrete, Dumpy Level, Gravel, Soil, Asphalt, Stud Counter and Feet & Inches. Each draws a live diagram of the job as you type, works in millimetres by default (feet, inches and sixteenths under Settings ▸ Units ▸ Default units), and runs on the phone, so it works with no signal. Concrete, Stairs and Check Square are free; the other 13 unlock with a weekly subscription (3-day free trial) or a one-time lifetime unlock. It runs on Android 7.0 or later.
What it does not do: rafter, hip and valley cuts, birdsmouths, stair landings and winders, roof area and feet-inch keypad arithmetic. The trade pages say where that matters. To see how MeisterCalc stacks up against other apps and web calculators, read the comparisons.