Concrete, Roof & Material Estimator

Calculate concrete slab volume and bag counts, determine roof pitch slopes and angles, or estimate stud framing requirements for DIY projects.

Roof-pitch mode focuses on rise/run, slope angle, and rafter multiplier. Confirm structural span, local code, and roofing product requirements.

Material estimate only. Add waste, check local code, product coverage, load requirements, and site conditions before ordering or building.

Required Construction Materials

6/12Roof Pitch Slope
Roof Angle (degrees)26.57°
Rafter Length Multiplier1.1180

Estimating Steps:

1. Slope ratio = 6 in rise for every 12 in run
2. Slope angle = arctan(6/12) = 26.57°
3. Roof Length Multiplier (Rafter Factor) = √[1 + (Rise/Run)²] = 1.1180
   (Multiply flat roof projection area by 1.1180 to find real pitched roof surface area.)

Frequently Asked Questions

How many bags of concrete make a cubic yard?

It takes about 45 80-pound bags or 60 60-pound bags of premixed concrete to equal one cubic yard before waste or product-specific yield adjustments.

What is a standard roof pitch?

Residential roof pitches typically range from 4/12 (low slope) to 9/12 (steep). A 4/12 pitch means the roof rises 4 inches for every 12 inches of horizontal run.