RenoScribeMeasure & Make

Rectangular slabs / volume and bags

Concrete calculator

Estimate a rectangular slab volume and whole bags using the yield printed on the bag. For structural work, defer to the plans, code and a qualified professional.

MEASURE / Rectangular slab

Concrete calculator

MAKE / MATERIAL PLAN

37whole bags to buy
Order volume
0.815 yd³
Metric volume
0.623 m³
Before allowance
20 cu ft

For structural work, confirm thickness, reinforcement, base preparation and local code with a qualified professional.

How the estimate is calculated

  1. Depth in feet = depth in inches / 12.
  2. Base volume = length x width x depth.
  3. Order volume = base volume x (1 + allowance).
  4. Bags = order volume / bag yield, rounded up.

The volume is also converted to cubic yards and cubic meters. Irregular excavation and changing depth require separate sections or field verification.

Before placing concrete

Confirm excavation, compacted base, forms, reinforcement and drainage.

Check minimum thickness, weather limits, working time and local requirements.

For larger pours, compare ready-mix delivery with the labor and consistency of bag mixing.