How to Estimate a Concrete Job (Cubic Yards, Base & Finish)
Concrete is unforgiving to estimate: once it's poured, a short order or a thin base is expensive to fix. Here's how to estimate a concrete job from area and thickness so the yards — and the margin — come out right.
8 min readA concrete estimate is mostly two calculations done carefully: how many cubic yards you're pouring, and what it takes to prep and finish them. Order short and you're stopping a pour to chase more mud; skimp on base or rebar and the slab cracks and the call-back is yours. This guide works the job in order — measure, convert to yards with waste, then price prep, materials, and finish labor.
1. Measure the area and the thickness
Start with the surface: length × width gives square feet for a slab, driveway, or patio. Then pin the thickness — four inches is typical for a residential slab or driveway, more for heavy loads — because thickness drives the volume directly. For footings and irregular shapes, break the pour into rectangles and prisms and measure each, rather than averaging a complex form.
- Measure each section separately and add the volumes — don't average an L-shaped or stepped pour.
- Confirm the finished thickness, including any thickened edges, before you compute yards.
- Note access for the truck or pump now — a long wheelbarrow run or a pump changes your labor.
2. Convert to cubic yards — and add for waste
Concrete is ordered by the cubic yard. Multiply square feet by thickness in feet (four inches is 0.33 ft), then divide by 27 to get yards. Always add a waste and over-excavation allowance — commonly 5–10% — because forms flex, subgrade is never perfectly level, and you do not want to come up short on a pour. Round up to the way your supplier sells it, and confirm any short-load fee for small jobs.
3. Quantify the materials beyond the concrete
The mud is only part of the materials. A proper slab sits on a compacted gravel base, often over a vapor barrier, and is reinforced with rebar or wire mesh. Forms, stakes, and release agent are consumables every pour needs. Build the list once and the quantities scale off your area and yards.
- Ready-mix concrete: (area × thickness in ft) ÷ 27, plus 5–10% waste, in cubic yards.
- Gravel base: by the ton or yard for the compacted sub-base.
- Reinforcement: rebar by the linear foot or wire mesh by the area.
- Forms, stakes, release, and a vapor barrier where required, as a lot.
How an estimate comes together
Measure
Take field measurements — area, counts, linear feet.
Quantify
Convert to material quantities and labor hours, with a waste factor.
Price
Apply unit costs and your markup to each line item.
Total
Subtotal, contractor fee, and tax recompute automatically.
4. Price site prep and the pour
Site prep is real labor: excavation and haul-off, grading, and compacting the base to the right depth. Then there's the pour itself — placing, screeding, and the cost of a pump truck if the truck can't reach the forms. Price these as their own lines because they vary enormously with access and soil. A driveway you can back the truck up to is a different job from a backyard patio you have to wheel or pump to.
5. Add finish labor, then mark up
Finishing is skilled, time-sensitive work — floating, troweling, edging, broom or stamped finish, then cutting control joints and curing — and it's priced by the hour at your finisher's loaded rate. Decorative finishes (stamping, coloring, exposed aggregate) carry their own higher line. Then mark up your materials to cover pickup, the waste you ordered, and sourcing. Apply the markup consistently so a few cents per square foot don't quietly erase your margin.
Skip the spreadsheet: open a concrete estimate already split into site prep, materials, and labor — then drop in your own yards and rates.
Open a prefilled concrete estimate6. A worked example: a concrete driveway
Take a driveway of about 1,000 square feet at four inches, which works out to roughly 12–13 cubic yards before waste and about 14 after a 10% allowance. Lay it out in three sections — site prep, materials, and labor — and the totals follow once you set your own yard price, base cost, and finishing rate. The numbers are structure; your region and access decide the dollars.
- Site prep: excavation and grading + the compacted gravel base.
- Materials: ready-mix concrete (cu yd), rebar or mesh, forms and release.
- Labor: form, pour, and finish + cutting control joints and curing.
- Then: apply your markup, fold in your contractor fee, and add tax for your jurisdiction.
Illustrative example only — not a quote. These figures are a starting skeleton; real material costs, labor rates, quantities, waste factors, and local pricing vary widely. You alone decide your prices and are solely responsible for verifying every number before sending an estimate. Bill-The-Job does not validate these figures and is not liable for estimates you produce.
7. Present it like a pro and send it fast
A clean estimate that separates base and prep from the pour and finish shows the homeowner why a proper slab costs more than 'just concrete' — and protects you when a cheaper bid skips the base. Group the work, take a deposit to cover the mud order, and send a branded PDF the same day. Bill-The-Job computes every total exactly and turns the accepted estimate into an invoice in one tap.
Build a concrete estimate now — site prep, materials, and finish labor, totaled exactly — then save it to a free account to send a clean, unwatermarked PDF.
Build your concrete estimate freeWork in your language, bill in your client's
Plenty of contractors run the whole job in one language and have a client who reads another — a Spanish-speaking crew and an English-speaking homeowner, or a Spanish-speaking owner and an English-speaking GC. You shouldn't have to choose. Write the estimate in the language you think in, then hand the client a clean document in theirs — English or Spanish — with every quantity, unit price, and total carried across unchanged. The language gets translated; the numbers never do.
See how to estimate in one language and invoice in your client's — Spanish or English — without re-keying a single number.
Invoice in your client's languageFrequently asked questions
Multiply the area in square feet by the thickness in feet (four inches is 0.33 ft), then divide by 27. For example, 1,000 sq ft at four inches is about 12.3 cubic yards before waste. Always add a 5–10% allowance for over-excavation and form flex so you don't come up short on the pour.
Commonly 5–10%. Subgrade is never perfectly level, forms flex, and spillage happens, so ordering exactly to the math risks stopping the pour to chase more concrete. Round up to how your supplier sells it and confirm any short-load fee on small jobs.
It depends on the load and local practice. Wire mesh is common for residential slabs and sidewalks; rebar is used for driveways, thicker slabs, and anything carrying heavier loads. Price the reinforcement the job actually calls for and note it as its own line so the client sees it's included.
Four inches is typical for standard residential vehicle traffic, with thicker sections or a deeper base where heavier vehicles park. Thickness drives your cubic yards directly, so confirm it before you compute volume — and price a proper compacted base, since that's what keeps the slab from cracking.
Access (can the truck reach the forms, or do you need a pump), site prep and base depth, reinforcement, and the finish all move the number. A decorative stamped or colored finish costs well above a broom finish. A bid that looks cheap often skipped the base or the reinforcement.
It depends on your state — some tax materials but not labor, some tax both. Confirm the rules for your jurisdiction and set the tax rate accordingly. This guide and the prefilled template are illustrative only and not tax advice.