#concrete

Reinforcement-steel (rebar) maths as an API, computed locally and deterministically. The area endpoint computes the cross-sectional area of a reinforcing bar, a = π/4·d², its mass per metre (a·7850/1e6, steel ρ = 7850 kg/m³), the total area and mass for a number of bars, and — given a required steel area — the number of bars needed and the area provided. The spacing endpoint lays out bars across a section: from the width, the cover, the bar diameter and either a centre-to-centre spacing or a bar count it returns the other, n = floor((width − 2·cover − d)/spacing) + 1, the total steel area and the area per metre of width. The ratio endpoint computes the reinforcement ratio ρ = As/(b·d) of a section from the steel area (or the bars) and the section width and effective depth, as a fraction and a percentage, the single number that governs whether a beam is under- or over-reinforced. Everything is computed locally and deterministically, so it is instant and private. Ideal for structural and site-engineering tools, reinforced-concrete detailing, bar-bending schedules and steel take-off, and civil-engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is rebar geometry and quantities; for concrete mix proportions use a concrete API.

api.oanor.com/rebar-api

Concrete mix-design maths as an API, computed locally and deterministically. The mix endpoint breaks down a volume of concrete into its materials from a nominal mix ratio (cement:sand:aggregate, for example 1:2:4): it applies the 1.54 dry-volume allowance, then returns the cement in cubic metres, kilograms and 50 kg bags, the sand and aggregate volumes and masses, and the water from the water-cement ratio — the complete batch for the pour. The quantity endpoint computes the concrete volume of a slab, footing, or round or square column from its dimensions, adds a wastage allowance and gives the dry material volume. The watercement endpoint solves the water-cement ratio, the water or the cement from the other two — the single most important number for concrete strength and durability. Densities used are cement 1440, sand 1600 and aggregate 1450 kg/m³, with a 50 kg cement bag. Everything is computed locally and deterministically, so it is instant and private. Ideal for construction, estimating and site-engineering tools, material take-off and ordering, DIY and builder apps, and civil-engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is nominal volume-batch concrete estimating; for retaining-wall earth pressure use an earth-pressure API.

api.oanor.com/concrete-api

Construction and material estimating as an API — the everyday "how much do I need to buy" maths for building and renovation jobs, computed locally and deterministically from standard geometry and trade rules of thumb. The paint endpoint works out the litres and number of cans for a surface, allowing for the number of coats and the paint's coverage and deducting doors and windows. The tile endpoint computes how many tiles (and full boxes) a floor or wall area needs from the tile dimensions and a wastage allowance. The concrete endpoint gives the concrete volume in cubic metres, cubic yards and litres — and the number of pre-mix bags — for a slab, footing, wall or round column, with an optional batch quantity. The bricks endpoint computes how many bricks a wall needs from the brick size and mortar joint (default 215×65 mm brick with a 10 mm joint ≈ 60 bricks per square metre). Everything is computed locally and deterministically, so it is instant and private. Ideal for builders' merchants and trade apps, DIY and home-improvement tools, quoting and estimating software, and project planners. Pure local computation — no key, no third-party service, instant. Live, nothing stored. Estimates are guidance — allow for site conditions and follow the manufacturer's stated figures. 4 endpoints. This is materials estimating; for plain unit conversion use a unit-conversion API and for tyre or drivetrain maths use a tyre API.

api.oanor.com/buildcalc-api