Most homeowners buy 20-30% more concrete mix than they actually need. The math isn't hard — it's just annoying to do on-site with a tape measure in one hand and your phone in the other.

Here's the thing most people get wrong: they calculate volume but forget to account for the mix ratio. A 4000 PSI coastal mix uses completely different proportions than a standard 3000 PSI slab mix. Same volume, different material amounts.

Quick reference for a standard 4" patio slab (3000 PSI):

• 10×10 ft = ~1.23 cubic yards

• That's roughly 45 shovels of gravel, 30 shovels of sand, 15 shovels of cement

• About 6-7 gallons of water (less if your sand is damp)

But if you're near the coast? Swap in sulfate-resistant cement and adjust your water-cement ratio down to 0.45. Different game entirely.

I built MixRight to handle all of this automatically — plug in your dimensions, pick your environment, and get exact amounts broken down to the tools you actually have on-site. No spreadsheets, no guesswork.