Engineering · 11 calculators
Concrete, beam and column loads, slabs, rebar, concrete mix, excavation and earthwork, stairs, brickwork and footings.
Civil Engineering
Concrete volume for a slab, footing, column or post hole, with cement, sand, aggregate and bag counts.
Volume = length × width × depth (× π/4 × …
Also called concrete volume calculator · how much concrete do i need
Civil Engineering
Reactions, maximum bending moment and shear for a simply supported beam under common loads.
UDL: M = wL²/8
Also called simply supported beam · beam reaction calculator
Civil Engineering
Axial capacity of a column and its Euler buckling load, with the slenderness ratio.
P_cr = π²EI / (KL)²
Also called euler buckling · column capacity
Civil Engineering
Concrete, mesh and formwork for a floor slab, driveway or patio, with the bag count and cost.
Volume = area × thickness × (1 + waste)
Also called slab concrete calculator · driveway concrete
Civil Engineering
Reinforcing bar for a slab or footing — bar count, total length, weight and lap allowance.
bars = clear span ÷ spacing + 1, in each …
Also called reinforcement calculator · steel bar calculator
Civil Engineering
Cement, sand, aggregate and water for any mix ratio and volume, by weight and by bag.
dry volume = wet × 1.54, then split by th…
Also called mix ratio calculator · cement sand aggregate ratio
Civil Engineering
Excavation volume, bulked spoil and truck loads for a trench, pit or basement dig.
bulked volume = in-situ volume × (1 + bul…
Also called dig volume calculator · trench excavation
Civil Engineering
Cut and fill volumes for levelling a site, with the net import or export of material.
net = cut volume − compacted fill volume
Also called cut and fill calculator · site levelling
Civil Engineering
Rise, going, step count and total run for a staircase, checked against building regulations.
risers = ceil(height ÷ max rise)
Also called staircase calculator · stair rise and run
Civil Engineering
Bricks needed for a wall, with mortar quantity, waste allowance and cost.
bricks = wall area ÷ (brick length + join…
Also called how many bricks do i need · brick quantity calculator
Civil Engineering
Concrete for strip or pad footings, including multiple footings and the total excavation volume.
Volume = length × width × depth × number …
Also called strip footing calculator · pad footing concrete
| Concrete | Volume = length × width × depth (× π/4 × d² for round) |
|---|---|
| Beam Load | UDL: M = wL²/8 · Central point: M = PL/4 · Offset: M = Pab/L |
| Column Load | P_cr = π²EI / (KL)² · slenderness = KL / r |
| Concrete Slab | Volume = area × thickness × (1 + waste) |
| Rebar | bars = clear span ÷ spacing + 1, in each direction |
| Concrete Mix Ratio | dry volume = wet × 1.54, then split by the ratio parts |
| Excavation | bulked volume = in-situ volume × (1 + bulking factor) |
| Earthwork | net = cut volume − compacted fill volume |
| Stair | risers = ceil(height ÷ max rise) · rise = height ÷ risers |
| Brick | bricks = wall area ÷ (brick length + joint) × (brick height + joint) |
For a 1:1.5:3 (M20) mix, roughly 8 bags of 50 kg cement per cubic metre, plus 0.42 m³ sand and 0.84 m³ aggregate.
One resting on two supports that can rotate freely — no fixed end moments. It is the standard idealisation for a joist or lintel.
Dry materials lose volume when water fills the voids between particles. The 1.54 factor converts the wet volume you need into the dry materials to buy.
Around 180 mm rise and 250 mm going for a domestic staircase, giving an angle of about 36°.
Standard UK bricks at a 10 mm joint give 60 bricks per m² for a single skin, or 120 for a one-brick wall.