Concrete Calculator

Choose a shape, enter dimensions (US or metric), add a waste factor, and if you like prices. You’ll get cubic yards/meters, 80/60/40 lb bag counts, and a ready-mix cost estimate.

Overview

This concrete calculator helps you plan pours for slabs, footings, columns, and stairs without guesswork. Enter your dimensions, pick US or metric units, and add an optional waste factor or price per yard. The tool automatically figures cubic yards/meters, 80/60/40 lb bag counts, and total cost so you can budget your mix and delivery accurately.

Use it for driveways, footings, small pads, steps, or formwork takeoffs. Each shape tab runs its own formula, so you can handle everything from simple flatwork to multi-step stairs. Add your bag or ready-mix prices to estimate materials fast and export your results as a CSV for your project file or quote.

Note: results are approximate. Site conditions, mix design, and compaction affect real yield. When unsure, round up and confirm with your local ready-mix supplier. Related materials: Asphalt · Lumber · Tile

How to use Results explained Rules & assumptions FAQ
Bag yields (approx): 80 lb ≈ 0.60 ft³, 60 lb ≈ 0.45 ft³, 40 lb ≈ 0.30 ft³.

Rectangular slab

US: L/W in feet, thickness in inches

Totals

Concrete needed— yd³

Bag counts & cost

Optional ad slot

How to use

  1. Select Units and set a waste/overage (5–15% is common).
  2. Pick the shape tab (slab, trench, column, or stairs) and enter dimensions.
  3. Optional: add prices for ready-mix per yd³ and bag prices to estimate cost.
  4. Click Calculate. Review the per-shape details, Totals, and Bag counts & cost.
  5. Download a CSV from each shape tab for your records or takeoff file.

Tip: thickness and depth vary by use and local code. When unsure, round up and add waste.

Results explained

Rules & assumptions

FAQ

How much waste should I add?

Typically 5–15% depending on site conditions, forms, and finish. Slabs with variable subgrade or complex forms often need more.

What’s the minimum ready-mix order?

Many suppliers have ~1–3 yd³ minimums and charge short-load fees below that. Call local plants for current policies.

Are bag yields exact?

No—0.60/0.45/0.30 ft³ are typical. Moisture, compaction, and mix design change yield. Always round up.

Can I enter multiple shapes together?

Calculate each shape and export CSVs; combine them in a spreadsheet to sum totals for complex pours.