m
m
m
%
Volume (m³)
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Volume + waste (m³)
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25kg bags (~12.5L each)
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Concrete Calculator for Slabs and Footings

Pulled off the highway to pour a quick pad for a picnic table at your next stopover? Building a small footing for a sign at that roadside diner you're fixing up between trips? The Concrete Calculator is your co-pilot for any pour, big or small. Punch in your slab or footing dimensions and you'll get the cubic yards (or meters) plus the exact number of bags you need to grab at the next hardware store you roll past. No more guessing in the parking lot, no more buying twice as much mix as you need, and definitely no more running short halfway through a pour with daylight burning. Whether you're

How to use Concrete Calculator for Slabs and Footings

  1. Pick your shape. Choose slab or footing depending on what you're pouring at your next stop.
  2. Enter dimensions. Type in the length, width, and thickness (or depth) in feet, inches, or meters.
  3. Choose your bag size. Select 40 lb, 60 lb, or 80 lb bags so the math matches what's stocked at the local hardware store.
  4. Hit calculate. Get total volume in cubic yards or cubic meters, plus the number of bags to grab.
  5. Add a buffer. Round up by 5-10% to cover spillage and uneven ground — better than driving back for one more bag.
  6. Load up and pour. Take the bag count straight to checkout, then head to the site and get to work.

Frequently asked

How accurate is the bag count? It's based on the yield printed on standard bags. Always grab a couple extra to cover spillage, an uneven subgrade, or that one corner you forgot to measure.
Can I use it for round footings or piers? Yes — switch to the footing mode and enter diameter and depth instead of length and width. It'll spit out the same volume and bag totals.
What units does it support? Feet and inches for slab dimensions, plus a metric option for cubic meters. Bag sizes cover the common 40, 60, and 80 lb options.
Do I really need to overshoot? Pretty much always. A 10% buffer keeps you from running out mid-pour, which matters when the nearest hardware store is 30 miles back the way you came.
Can I save the result? Snap a screenshot or just leave the tab open. The calculator runs in your browser, so it works even with spotty signal at a remote site.
Does it handle stepped or irregular slabs? Break the pour into rectangles, calculate each, and add the bag totals together. Works great for L-shaped pads or staggered footings.
Is it free? Yep, completely free and no signup. Bookmark it on your phone for the next pit stop project.
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