Concrete Bag Calculator — How Many Bags Do I Need?

Not every concrete job needs a truck. Fence posts, mailbox footings, small repair patches, sono tubes for a deck — these are bag mix jobs. The question is always the same: how many bags do I need?

Get it wrong and you're either making a second trip to the hardware store or you've got leftover bags hardening in your garage. BagMix Pro takes the guessing out of it.

What BagMix Pro Calculates

• Sono tubes — enter diameter, depth, and quantity. Get exact bag count.
• Slabs — length, width, thickness. Volume converted to bags.
• Footings — continuous or pad style, with volume and bag count.
• Bag sizes — supports 20kg, 25kg, 30kg, 40kg, and 80lb bags. Pick what your supplier carries.
• Extra bags — add a buffer for waste and spillage.

Why Bag Size Matters

A 30kg bag doesn't fill the same volume as an 80lb bag. The coverage rates are different. BagMix Pro knows the yield for every bag size so you get an accurate count regardless of what's available at your local supplier. If you're in Canada buying metric bags or in the US buying 80-pounders, the math is right either way.

Completely Free

BagMix Pro is free. No account, no trial period, no subscription. Open it on your phone, punch in your dimensions, and know exactly how many bags to throw in the truck. It works offline too — because half the time you're calculating this in a parking lot with no signal.