Draw the slab. Get the bid.

Trace the pour on screen. ConCal returns cubic yards, rebar with Class B laps, waste factor, and a bid-ready cost sheet, all before the coffee goes cold.

Start free trial Try the free calculator
14-day free trial Imperial & metric Works in the truck
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DRAWN6.9 CY BID$2,740 JOHNSON DRIVEWAY
6.9 CYJOHNSON DRIVEWAY · BID $2,740
A concrete driveway curving around a lawn, its boundary drawn.
A straight concrete driveway and the walk to the front door, boundary drawn.
Four townhouse driveway aprons and the sidewalk across them, boundary drawn.
A long concrete driveway running up through pine woods to a house, its boundary drawn.
A wide concrete driveway apron in front of a two-car garage, its boundary drawn.
A concrete driveway apron with the walk to the front porch, its boundary drawn.
A concrete truck pouring a formed slab, the forms drawn as one outline.

Stop guessing.

Every contractor has bid a job from a bounding box and a hunch, then eaten the short-load fee when the math came up a yard light. Drag the handle.

OVER- POUR ? ? ? ? 24 × 21… call it? ± ?? CY 24 × 21 = 504 sf ÷ 27 = 9.3 yd?? or 7? those two angles? −? + 10% waste?? rebar? ask Mike TOTAL = $ ____ ?
With ConCal
The old way
DRAG TO COMPARE · EYEBALLED RECTANGLE ±?? CY → DRAWN POLYGON 6.9 CY

Not everything is a rectangle.

Slabs, bump-outs, radius work, stem walls, column grids. Each drawn in its own projection, quantified to the yard.

A concrete driveway curving around a lawn, with its boundary drawn as one outline.
A real drive, traced. The curve comes out as a curve, not a rectangle that happens to be close.

Stop profit leaks before they happen.

Three line items quietly eat margin on hand-figured bids. ConCal closes each one at draw time, not at the plant.

Over-pour auditSHEET 01 · JOHNSON DRIVEWAY
23′7″ 19′1″ +1.4 CY 6.9 CY @ 6″
Eyeballed bounding boxDrawn polygon
Eyeballed bbox, 23′7″ × 19′1″8.3 CY
Drawn polygon, 6″ slab6.9 CY
Over-pour, every pour+1.4 CY
At an assumed $165/CY≈ $231
Over 33 pours a year$7,600 kept

The same driveway drawn at the top of this page. Worked example, not a quote. The yard price and the pour count are assumptions, and every figure above is checkable from the two you can see. Swap in your own and the total moves, which is the point: ConCal only ever does the arithmetic on numbers you entered.

Waste factor miscalculations

A flat 10% on every pour over-orders simple slabs and under-orders anything with sub-grade variation. ConCal applies waste per shape, per pour condition.

Waste set per shape and pour condition

Rebar overlaps, skipped or doubled

Class B lap lengths change with bar size, and napkin math rounds them off. ConCal adds laps to every run automatically and totals true LF.

Class B laps added per bar size

Volume estimation errors

Eyeballing an L-shape as a rectangle pours concrete into ground that isn't yours. Drawn polygons compute the exact CY of what you'll actually form.

Exact CY from the drawn polygon
A slab on grade part way through a pump pour: the rebar mat is set and tied with column starters standing, wet concrete covers the left half, and four workers in hi-vis stand on the mat.

How this started.

Back in 2023 I was working for a concrete contractor, pouring a slab with weird angles that was impossible to estimate. My boss said the line that started all of this: “Jared, you’re smart. Why don’t you figure out how much concrete I need to order?”

I sat down and worked it out by hand. It took hours, and I still had the quiet worry I’d got it wrong. Order too much and he eats the cost, run short on a 95 degree day and it’s worse. Every calculator I could find did circles, squares and rectangles. So I built the one we actually needed.

JaredFounder, ConCal Read the whole story
  • 2023Figured a weird-shaped pour by hand and thought there had to be a better way.
  • Rev 3Draw the job, get the takeoff, price it, send the proposal.
  • Your numbersEvery feature exists because the job needed it. No regional averages, ever.

Measure once. Bid once.

Draw any shape

Slabs, L-shapes, bump-outs, curves. Snap vertices, get exact square footage.

Footings, walls & columns

Continuous footings by LF, stem walls by height, columns by count. One takeoff.

Bid-ready cost sheet

Mix PSI, pump time, short-load fees, and labor, all totaled into a number you can sign.

Built for the field

Works offline in the truck, dark mode for 5 AM pours, autosaves every change.

Straight answers.

Does it work on my phone, in the truck?

Yes. ConCal runs in any phone, tablet or laptop browser, nothing to install. Your drawing autosaves on the device as you work, and cloud sync catches up when you're back on signal. Dark mode for the 5 AM pours.

Do I have to enter my own prices?

Yes, on purpose. ConCal never guesses regional averages. The 2-minute setup takes your real supplier quotes and labor rates, so every bid is your number, not somebody's national estimate. Change a price once and every future bid uses it.

What can it actually take off?

Slabs with bump-outs and curves, L-shapes, thickened edges, continuous footings by the foot, stem walls, and columns. Rebar (Class B laps included), wire mesh, base rock, and saw cuts are computed from the drawn geometry. If you can sketch it, it prices it.

What happens after the 14-day trial?

It's $44/mo if you stay. Nothing is charged until the 14-day trial ends, and your projects, price book and proposals stay saved in your account either way.

Is my pricing private?

Your price book and bids live in your account and go only where you send them: a proposal PDF or a share link you create. No marketplace, no selling your numbers, cancel whenever.

Want to kick the tires first? Try the free calculator No signup. Yards, mix and a materials list in about 60 seconds.

Bid your next job in ConCal.

Draw it once. The yards, the rebar and the dollars all trace back to a rate you set.

Start free trial See what's included

$44/mo · 14-day free trial · Cancel anytime