SPECIFICATION: Workshop Base, Large Outdoor Kitchen Patio, Heavy Shed

12×16 Concrete Slab Calculator (Patio, Shed & Workshop)

Covering 192 square feet, a 12×16 concrete slab at 4 inches thick requires 2.37 net cubic yards (2.61 cubic yards with 10% safety buffer). This equals 118 bags of 80 lb concrete (nearly 3 full pallets). At this volume, professional contractors consistently recommend ready-mix truck delivery to avoid cold seams.

SLAB DIMENSIONS192 SQ FT
THICKNESS (INCHES)4" Depth
+10%
DIY Retail Bag Weight:
Live Structural Cross-Section
16' × 12' Slab (4" Depth)
Structural cross-section of 16' x 12' concrete slab4" CONCRETE4" #57 STONE#4 REBAR @ 18" O.C.10 MIL VAPOR BARRIERCOMPACTED SUBGRADESPAN: 16 FT × 12 FT
Net Volume:2.37 cu yds
Order (+Waste):2.61 cu yds
Base Prep:4" Crushed Base
Reinforcement:#4 @ 18" O.C.
Yield Comparison (16' × 12')
DIY RETAIL STORE PICKUP
118 Bags
80 lb bags (~3 full pallets)
Dry Weight:9,440 lbs
Est. Bag Cost:$767
COMMERCIAL READY-MIX
2.61 cu yds
1 mixer truck (3500 PSI)
Delivery Scale:Recommended for Ready-Mix
Est. Ready-Mix:$475

Frequently Asked Questions: 12×16 Concrete Slab Calculator (Patio, Shed & Workshop)

How many 80 lb bags for a 12x16 slab?

You will need 118 bags of 80 lb concrete mix (or 157 bags of 60 lb mix) factoring in a 10% waste contingency.

Should I pour a 12x16 slab with bags or a ready-mix truck?

Call a ready-mix truck. Moving and mixing 9,440 lbs of dry concrete bags by hand will exhaust a DIY crew and almost certainly result in cold joints. A truck chute pours 2.6 yards in under 15 minutes.

What rebar spacing is needed for a 12x16 slab?

#4 (1/2") rebar arranged in an 18" on-center grid requires 16 sticks of 20-foot rebar, supported by 25 plastic chairs to ensure the steel sits in the center third of the slab depth.