Example data table
| Scenario | Inputs | Key outputs |
|---|---|---|
| Straight ramp with landing |
L=12 ft, W=4 ft, Rise=12 in, Start t=0 in Landing=3 ft, Landing t=4 in, Waste=5% Labor=2.5 mh/yd³, Crew=3, Rate=$45/hr Material=$160/yd³, O/H=10%, Profit=10% |
Net ≈ 1.037 yd³ (0.793 m³) Materials ≈ 1.089 yd³ with waste Labor ≈ 2.59 man-hrs (0.86 crew-hrs) Total ≈ $349.07 |
Formula used
- End thickness: t1 = t0 + rise
- Ramp volume (average thickness method): V_ramp = L × W × (t0 + t1) ÷ 2
- Landing volume: V_land = L_land × W × t_land
- Net volume: V_net = V_ramp + V_land
- Material ordering volume: V_mat = V_net × (1 + waste%)
- Man-hours: MH = V_net × (man-hours per unit)
- Labor cost: Cost_labor = MH × hourly rate
- Total cost: Total = (labor + material) × (1 + overhead% + profit%)
How to use this calculator
- Select Imperial or Metric units.
- Enter ramp length, width, rise, and start thickness.
- Enable a landing if needed, then add its length and thickness.
- Set a realistic waste factor for ordering concrete.
- Choose a labor basis and enter your man-hours per unit.
- Provide crew size, rate, material pricing, overhead, and profit.
- Press Calculate. Use the download buttons in Results.
Ramp volume and labor planning notes
1) Geometry inputs and assumptions
Ramp volume is driven by length, clear width, rise, and start thickness. The calculator treats the ramp as a straight prism with linearly changing thickness and can add an optional landing slab. When you have curves, flares, or slope breaks, split the work into segments and sum the results. Subtract drains or block-outs, and model thickened edges as separate strips when they extend beyond the main thickness. Keep separate takeoffs for rebar, dowels, and edge forms.
2) Unit handling and conversion
Choose a unit system before measuring so field notes match the entry fields. Small thickness errors compound quickly: a 10 mm overstatement across a 12 m by 1.5 m ramp adds roughly 0.18 m³. In customary work, thickness is often recorded in inches while length and width are in feet; consistent units avoid hidden conversion mistakes.
3) Waste factor and ordering volume
Waste covers subgrade irregularities, over-excavation, spillage, and finishing losses. For stable forms and subgrade, 3–7% is a practical starting range; for difficult access, long pump lines, or uneven bases, 8–12% is more realistic. Use the material price field to translate ordered volume into direct concrete cost and compare alternates.
4) Labor productivity and crew sizing
Man-hours are calculated from net volume and a productivity rate, so set the rate to match placement method. Hand placement with tight access can require 6–10 man-hours per m³, while direct chute or short pump runs often fall near 3–6. Crew size affects duration: duration ≈ man-hours ÷ crew size, helping plan finishing and curing protection.
5) Cost build-up and reporting
Total cost combines labor and material, then applies overhead and profit as percentages. Use overhead for supervision, small tools, mobilization, and quality checks; use profit for margin and risk. CSV supports quick review in estimating sheets, while the PDF output provides a clean record for submittals and internal approvals. Document assumptions in notes and verify quantities against drawings and measurements.
FAQs
1) What ramp shape does the calculator assume?
It assumes a straight ramp with thickness changing linearly from start thickness to end thickness, plus an optional rectangular landing. For curves or slope breaks, calculate each segment and add the totals.
2) Should I enter rise or slope percentage?
Enter the total rise. Slope percent is derived from rise ÷ length. If you only know a slope ratio, convert it to rise by multiplying the ratio by the ramp length.
3) Why are there two volumes: net and ordering?
Net volume is the theoretical placed concrete. Ordering volume adds the waste factor for field losses and irregularities. Use ordering volume for supplier requests and net volume for labor and cost tracking.
4) How do I pick a man-hours per unit value?
Start from your past work and adjust for access, reinforcement congestion, finishing requirements, and weather. Tight sites and heavy detailing increase the value; straightforward pours with good access usually reduce it.
5) Does crew size change man-hours?
No. Crew size changes duration, not total man-hours. A larger crew can finish faster, but delivery rate, finishing capacity, and curing constraints still limit productivity on small ramps.
6) Can I use this for estimating cost only?
Yes. Enter a realistic productivity rate, hourly rate, and material unit price, then apply overhead and profit. Add separate items for reinforcement, joints, curing, and any special surface treatments.