Calculate road areas across segments using flexible units and shapes. Add wastage, thickness, weight, and costs. Download results instantly for busy teams on-site daily.
| Segment | Shape | Inputs | Area (m²) |
|---|---|---|---|
| 1 | Rectangle | L=120 m, W=7.5 m | 900.0000 |
| 2 | Trapezoid | L=30 m, W1=7.5 m, W2=9.0 m | 247.5000 |
| 3 | Circle | R=12 m | 452.3893 |
| Total | 1,599.8893 | ||
Road corridors rarely stay uniform. Break the alignment into measurable segments: straight rectangular runs, tapers as trapezoids, triangular splays at junctions, and circular areas for islands or roundabouts. Summing segment areas reduces survey errors and makes revisions easy when widths change.
For many urban carriageways, widths commonly fall between 3.0–3.7 m per lane, while shoulders may add 0.5–2.0 m. Segment lengths can be taken from chainage, drawings, or GIS polylines. A practical wastage allowance is often 3–8%, depending on joints, trimming, and site access. For surfacing layers, thicknesses frequently range from 30–80 mm.
Procurement needs quantities, not only area. This calculator converts working area to volume using Volume = Areawork × Thickness. With density (kg/m³), it estimates mass, helping you check truckloads and batching requirements. Example: 1,600 m² at 50 mm with 5% wastage gives 84.0 m³. At 2,320 kg/m³, that is about 194.9 tonnes.
Use the optional cost per m² for fast budget screening on the same working area that drives materials. Pair the area with crew outputs (m²/day) to estimate durations and staging. If cost or time looks abnormal, revisit segment widths, confirm chainage limits, and check whether shoulders, medians, or parking bays are included.
Keep units consistent: lengths and widths convert to meters internally, and thickness converts to meters from mm/in. Validate one segment at a time, then compare totals against plan-area schedules. For tapered sections, confirm both start and end widths. Record assumptions beside the exported files for transparent approvals.
1) When should I use trapezoid instead of rectangle?
Use trapezoid for tapers where width changes along a length, such as transitions, widening zones, and approach lanes. It averages the two widths over the segment length for a reliable takeoff.
2) What does “wastage” include in road works?
Wastage covers overlaps, trimming losses, construction tolerances, and small rework. Choose a percentage that matches your method statement and site constraints, then apply it consistently to procurement quantities.
3) Why does thickness affect volume and weight but not the base area?
Area is a surface measurement. Thickness converts that surface into a material quantity (volume), and density converts volume into mass. This helps align area takeoffs with mix designs and hauling plans.
4) Which density value should I enter?
Use the density specified in your project documents or supplier data. Typical values are around 2,320 kg/m³ for asphalt and 2,400 kg/m³ for concrete, but local mixes can differ.
5) Can I mix meters and feet within the same calculation?
Within a run, choose one length unit and one width unit for all segments. The calculator converts them internally, but mixing units segment-by-segment can create avoidable input mistakes.
6) How do I estimate cost accurately using cost per m²?
Enter a unit rate that matches your scope and layer type. The calculator multiplies that rate by the working area (including wastage), giving a quick screening total. For final pricing, add mobilization and indirects separately.
7) Why do my totals differ from drawing schedules?
Differences often come from excluded features (shoulders, medians), rounding, or taper assumptions. Re-check chainage limits, verify both widths in transitions, and ensure the same wastage approach is used in both estimates.
Plan, measure, and build smarter roads with confidence today.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.