03
Div 03 Concrete
Calculate cubic yards for slabs, footings, and columns. Includes ACI-318 compliant rebar logic and automated waste factors.
- Slab Volume
- Rebar Weight
- Block Wall (CMU)
- Sonotube Columns
Engineering Tools
From Driveways
to Roofs.
For the builder who switches between square footage and cement tonnage ten times a day. One interface. Zero guesswork.
Concrete Tool
Professional estimation standard.
Cubic Yards
FT
FT
Slab Thickness
Total Volume (+5% Waste)
5.19 YDS³
Engineered for Trades
Grouped by CSI MasterFormat™ divisions.
REF: SPEC-2025-V2
06
Div 06 Carpentry
Estimate framing lumber for walls, floors, and roofs. Switch instantly between 16" OC and 24" OC spacing logic.
- Wall Framing
- Floor Joists
- Deck Boards
- Sheathing (4x8)
31
Div 31 Earthwork
Determine material tonnage for driveways, patios, and landscaping. Convert volume to weight for gravel, sand, and mulch.
- Gravel Tonnage
- Asphalt Cost
- Excavation Volume
- French Drains
Calculation Methodologies
The engineering formulas powering our tools.
Concrete & Volume
We use the standard volumetric formula:
Length × Width × Depth / 27. This converts cubic feet into Cubic Yards, the standard unit for
Ready-Mix trucks.
Includes 5% Spillage Safety
Framing & Lumber
Stud counts are calculated based on On-Center (OC) spacing.
Total Length / Spacing + 1. Our algorithm automatically accounts for three-stud corners and double
top plates.
Supports 16" & 24" OC
Frequently Asked Questions
What is the formula for calculating concrete cubic yards?
To calculate cubic yards, multiply Length (ft) × Width (ft) × Depth (ft) to get cubic feet. Then, divide the total by 27.
Example: A 10x10 slab at 4 inches deep (0.33 ft) is 33 cubic feet. Divided by 27, that is 1.22 cubic yards.
Example: A 10x10 slab at 4 inches deep (0.33 ft) is 33 cubic feet. Divided by 27, that is 1.22 cubic yards.
How many 80lb bags of concrete are in a yard?
It takes 45 bags (80lb) to equal one cubic yard of concrete. If you are
using smaller 60lb bags, you will need 60 bags per yard.
How do you calculate studs for a wall 16 OC?
For 16-inch on-center spacing, convert your wall length to inches and divide by 16.
Always add:
- +1 stud for the end of the wall
- +2 studs for every 90° corner
- +2 studs for every window or door opening
What is a 'Square' in roofing terms?
One roofing "Square" equals 100 square feet of roof area. For standard
3-tab architectural shingles, you will need 3 bundles to cover one square.
Is BlueprintMath accurate for commercial bids?
Yes. Our calculators use standard engineering constants (ACI-318 for concrete, IBC
for framing). We do not round down. However, always verify local building codes
before ordering materials.
Pro Tips
Recommended Waste Factors
The #1 cost overrun in construction is estimating errors. Always calculate Net Volume first, then apply these safety margins:
- Concrete Slabs 5-10%
- Framing Lumber 15%
- Drywall 10%
- Roofing 10-15%
Field Reference & Constants
REF_DB_2025Concrete (3000 PSI)
| Wet Density | 4,050 lbs/yd³ |
| 80lb Bags / Yd³ | 45 Bags |
| 60lb Bags / Yd³ | 60 Bags |
| Slab Weight (4") | ~50 lbs/sq ft |
Lumber & Waste
| 16" OC Logic | 1 stud / 12" |
| Standard Waste | 10% - 15% |
| Drywall Weight | 50 lbs / sheet |
| Stud Trim Height | 92 5/8" |
Roofing Systems
| Bundles / Sq | 3 Bundles |
| Nails / Sq | ~320 Nails |
| Underlayment | 2 Rolls / 10 sq |
| Weight / Sq | 240 lbs |
Soil & Aggregate
| Gravel (Loose) | 2,500 lbs/yd³ |
| Topsoil (Loose) | 2,100 lbs/yd³ |
| Swell Factor | +20% |
| Compaction | -15% |