Sakrete For Slab Calculator

Instantly calculate the concrete volume, cubic yards, bags, and cubic feet you need for a slab – free and instant.

  • Free
  • No sign-up
  • Instant results

Loading calculator…

How to use it

  1. Enter length, width, and thickness in the fields.
  2. Click the Calculate button.
  3. Read the cubic yards, cubic feet, and bag count results.

What it does – Enter the slab’s length, width, and thickness and the tool instantly shows three key figures: total cubic feet, cubic yards, and how many 80‑lb Sakrete bags you’ll need. Why it matters – Knowing the exact volume prevents costly over‑ordering and ensures you have enough material to pour a solid, level slab the first time. How to read the results – Cubic feet is the raw volume; divide by 27 to see cubic yards, the unit most suppliers quote. Multiply cubic feet by the bag yield (0.6 ft³ per bag) to get the bag count, rounded up to the next whole bag. Use these numbers when calling your concrete supplier or budgeting the project. Most suppliers sell by the cubic yard, so the yard figure helps you compare pricing and order the right amount.

Pro tips

  • Add about 10% extra for waste and spillage
  • Round the bag total up to the next whole bag
  • Check the supplier’s minimum order size before buying
  • Measure slab thickness at several points for accuracy

Real-life examples

  • A homeowner planning a new garage floor needs to know how many Sakrete bags to order
  • A contractor estimating material for a patio slab wants precise yardage for a bid
  • A DIY gardener installing a raised garden bed wants to avoid over‑buying concrete

Case study

Maria entered her patio dimensions and got 2.4 cubic yards, which translated to 12 bags. She ordered exactly 12 bags, saved $45, and completed the pour without any mix left over.

Frequently asked questions

How many 80‑lb bags are needed for a 10 ft x 10 ft slab 4 in thick?
Enter the dimensions; the calculator will show the exact bag count based on 0.6 ft³ per bag.
What unit do concrete suppliers use for pricing?
Suppliers usually price by the cubic yard, so use the yard result for cost estimates.
Should I add extra concrete for waste?
Yes, add about 10% to the calculated volume to cover spillage and uneven sub‑grade.
Can I use the calculator for a slab that isn’t a rectangle?
Break irregular shapes into rectangles, calculate each, then sum the results.
Do I need to round up the bag number?
Always round up to the next whole bag; you can’t purchase a fraction of a bag.