MeasureTwice

Concrete hub

Concrete calculators for bags, yards, and cost.

Start with the slab calculator, then use the same estimating pattern for post holes, footings, walls, columns, stairs, curbs, and cost planning.

Slab estimate

Concrete slab calculator

Live estimate

Slab sketch

A simple rectangular pour with adjustable waste.

length width

Concrete tools

Pick the shape before you buy material

Different concrete shapes need different formulas. The hub keeps the shape decision close to the calculator.

MVP path

Slab is live first. Post holes and footings come next because their formulas and buying decisions are meaningfully different.

Shopping list

Ready to price and order

Use the calculated quantities as a starting cart, then compare store availability, delivery fees, pallet limits, and local ready-mix minimums before buying.

Primary material

62 bags

80 lb concrete mix

Use the calculated bag count as your buying starting point, then verify yield and pallet limits with the store.

Large pours

Ready-mix quote check

For high bag counts, compare the bagged route against local ready-mix minimums, delivery, access, and unload time.

Optional base

Gravel base

Base depth is project-specific. Estimate it separately before adding bags or bulk gravel to the order.

Optional forms

Forms and stakes

Plan lumber, stakes, screws, release, and bracing around the perimeter and any step-downs or curves.

Store buttons open retailer search results for now. Confirm exact product yield, pickup, delivery, and pallet rules before ordering.

Formula shown

How concrete estimates work

Slabs, footings, and walls

length ft x width ft x thickness ft

Round post holes and columns

pi x radius ft² x depth or height ft

Bags and yards

cubic yards = ft³ / 27; bags = ceil(ft³ with waste / bag yield)

Sources

Reviewed for estimating accuracy

Written by

MeasureTwice Editorial

DIY estimating and home-improvement research

Reviewed by

Mark Ellis

Concrete flatwork and small-project takeoffs

Last updated: June 20, 2026

Estimate only. This calculator is not a quote. Verify product yield, price, delivery minimums, and local conditions with your supplier or contractor before buying materials.

FAQ

Concrete calculator questions

Quick answers for choosing the right shape, comparing bags and ready-mix, and using waste allowance.

What concrete calculator should I use first? +

Use the slab calculator for patios, shed pads, walkways, and small rectangular pours. Use post-hole or footing calculators when the shape is different enough to change the formula.

Should I compare bags and ready-mix? +

Yes. Bagged concrete is convenient for small work, while ready-mix is usually easier for larger pours. The hub keeps both views visible so you can compare before buying.

Do concrete calculators include waste? +

MeasureTwice defaults to a 10% waste allowance, but each concrete calculator lets you type a custom percentage for your jobsite or quote comparison. Uneven subgrade, spillage, and form variation can all change final quantities.

Are these estimates a contractor quote? +

No. The calculators are estimating tools for planning quantities and rough material cost. Verify product yield, price, delivery minimums, and site conditions with your supplier or contractor.