The jobsite math, in one place.
Three everyday calculations, without hunting for three different apps. Concrete volume in cubic yards and bags, slope as pitch, degrees and percent, and conversion between decimal feet and feet-inches to the nearest sixteenth.
- Concrete yd³ & bags
- Pitch · degrees · %
- Feet-inch fractions
- Copy to your estimate
Slab, footing or pad
Rise and run
Convert
Save your results
Copy these results, then add your approved sample files in the trial brief.
Estimates only. Verify against project documents, manufacturer data and the governing code before you bid.
Numbers estimators look up every week.
| Need | Rule | Example |
|---|---|---|
| Cubic yards of concrete | L × W × (in ÷ 12) ÷ 27 | 20×20 ft at 4 in = 4.94 yd³ |
| Roof pitch to degrees | atan(rise ÷ run) | 6:12 = 26.57° |
| Pitch to percent grade | rise ÷ run × 100 | 6:12 = 50% |
| Inches to decimal feet | inches ÷ 12 | 4 3/8 in = 0.3646 ft |
| Cubic yards to m³ | × 0.7646 | 5 yd³ = 3.82 m³ |
Quick checks, not the whole takeoff.
Sanity-check a takeoff
Spot-check a slab or footing quantity before it goes into the bid.
Field conversions
Turn a scaled decimal dimension into something a crew can read off a tape.
Slope talk
Translate between pitch, degrees and percent when trades describe the same slope differently.
Calculators check one number. Bids need every quantity.
When a full plan set needs quantities, RenderDraw proposes them from the drawings with source references, and your estimator approves them before pricing.
- Source on every row. Each proposed quantity keeps the sheet and location it came from.
- Estimator approval before pricing. Your estimator accepts, corrects or rejects proposals; nothing is priced until it is approved.
- Addenda through the same review. Changed sheets go back through takeoff and estimator review.
- Your assemblies, your rates. Approved rows hand off to your assemblies, labor units and pricing inputs.
Construction calculator, answered.
How do I calculate cubic yards of concrete?
Multiply length × width in feet by thickness in inches ÷ 12 to get cubic feet, then divide by 27. A 20 × 20 ft slab at 4 inches is 133.3 ft³, or 4.94 yd³. Add waste for over-excavation and spillage.
How many 80 lb bags of concrete make a yard?
At about 0.6 ft³ per 80 lb bag, one cubic yard (27 ft³) takes about 45 bags. Check the yield printed on the bag you are using.
How do I convert roof pitch to degrees?
Take the arctangent of rise ÷ run. A 6:12 pitch is atan(0.5) ≈ 26.57°.
How do I convert decimal feet to feet and inches?
Keep the whole feet, multiply the decimal by 12 for inches, then round the leftover to the nearest 1/16. 12.5417 ft is 12' 6 1/2".
What is the difference between slope percent and pitch?
Pitch is rise per 12 units of run (6:12). Percent grade is rise ÷ run × 100 (50%). They describe the same slope.
Send one plan set. Judge the result yourself.
A focused, no-obligation evaluation on your own drawings. Your sample files remain private while we assess the request.
- Upload one representative plan set (a legible PDF set is the most reliable starting point), plus an addendum if you have one.
- RenderDraw reviews the set and the scope you want tested.
- We follow up with what was extracted, what was flagged for review, and the most useful next step.