A concrete bid lives or dies on two numbers: how much concrete the job needs, and how many crew-hours it takes to place and finish. Here is how to get both right.
A concrete bid lives or dies on two numbers: how much concrete the job actually needs, and how many crew-hours it takes to place and finish. Get either one wrong and you either price yourself out of the work or pour your profit into the slab. Here is how to estimate a concrete job so the bid holds up when the truck arrives.
Start with the volume, in cubic yards
Concrete is sold by the cubic yard, so every estimate starts by converting the job's dimensions into yards. Multiply length by width by thickness, but keep the units straight: thickness is in inches, so divide it by 12 to get feet, then divide the whole thing by 27 to convert cubic feet into cubic yards. A 30-by-40 slab at 4 inches is 30 x 40 x (4/12) / 27, about 14.8 yards.
Then add waste. Forms flex, the subgrade is never perfectly level, and you do not want to come up short with a finish crew standing around. Ten percent is a common over-order factor for flatwork; tight, well-formed pours can run less, rough sitework more.
Price the materials around the concrete
The ready-mix is the biggest material line, but it is rarely the only one. A real concrete estimate carries the base (gravel and compaction), reinforcement (rebar or wire mesh), the forms (lumber and stakes), a vapor barrier where it is called for, and the extras that quietly add up: rebar chairs, control-joint sawcutting, and sealer. If the pour needs a pump truck because the trucks cannot reach the forms, that is a line item, not a rounding error.
Quote each of these against your own supplier pricing, not a number you saw online last year. Local concrete and rebar prices move, and a bid built on stale costs is a bid that loses money quietly.
Estimate labor by productivity, not by gut
The honest way to price concrete labor is by production rate: how many square feet your crew places and finishes per crew-hour. A small flatwork crew on a clean slab might run 40 square feet per crew-hour; complex finishes, tight access, or hand-work pull that number down. Divide the job's square footage by your real rate to get crew-hours, then multiply by your burdened labor rate, the wage plus payroll taxes, workers comp, and insurance, not just the hourly wage.
That burden is where a lot of contractors underprice. If you bid off the base wage and pay the burden out of the margin, the job looks profitable and is not.
Add overhead and markup last
Materials plus labor is your direct cost, not your price. Your truck, your phone, your insurance, your time bidding the jobs you do not win, all of it has to be carried by the jobs you do win. Add your overhead, then your markup, and check the margin. Remember that markup and margin are not the same number: a 20 percent markup on cost is only about a 17 percent margin on the price.
Make it repeatable
The contractors who bid fast and accurately are not doing this math from scratch every time. They have their unit costs and production rates saved, and they plug in the dimensions. The Concrete Estimate Template does exactly that, dimensions to cubic yards with waste, materials and labor priced at your rates, and a bid price with the margin shown, plus a price book so your concrete unit costs are entered once and reused on every job.
If you run more than concrete, the Contractor Estimating & Job-Profit System carries the same logic across every trade with a client-ready proposal at the end. Both live in the Contractor & Trades tools.
Estimate the volume, price the real materials, cost the labor at a burdened rate with a production number you trust, and never let overhead and markup be an afterthought. Do that and the slab pays.