Project Inputs
Enter geometry for the curb and adjacent gutter slab. Choose a unit system, then fill every field with positive values.
Example Data
| Length (m) | Top width (m) | Bottom width (m) | Curb height (m) | Gutter width (m) | Gutter thickness (m) | Waste (%) | Volume incl. waste (m³) |
|---|---|---|---|---|---|---|---|
| 30 | 0.15 | 0.20 | 0.18 | 0.60 | 0.12 | 5 | 3.2603 |
| 60 | 0.18 | 0.25 | 0.20 | 0.75 | 0.13 | 6 | 8.9358 |
Examples are for illustration. Always confirm section details with your drawings and local standards.
Formula Used
- Curb cross‑section area (trapezoid): A₁ = (TopWidth + BottomWidth) ÷ 2 × Height
- Gutter cross‑section area (rectangle): A₂ = GutterWidth × GutterThickness
- Total area: A = A₁ + A₂
- Concrete volume: V = A × Length
- Waste allowance: Vᵥ = V × (1 + Waste% ÷ 100)
If the curb is rectangular, set top width equal to bottom width. For unusual profiles, split the section into simple shapes and add their areas.
How to Use This Calculator
- Select your unit system, then enter the run length.
- Enter curb top width, bottom width, and height from drawings.
- Enter gutter width and thickness for the adjacent slab section.
- Add a waste factor to cover overbreak, spillage, and trimming.
- Optionally include density and unit price for weight and cost.
- Press Calculate to see results above the form.
- Use the CSV or PDF buttons to export your calculation.
For field accuracy, measure actual formed widths and account for returns, transitions, and driveway flares as separate segments.
Technical Guidance
Geometry that drives concrete quantity
The curb portion is commonly approximated as a trapezoid because formed curbs often taper from a wider base to a narrower top. Using top width, bottom width, and curb height creates a reliable cross‑section area for estimating placed concrete. The gutter is treated as a rectangular slab defined by its width and thickness. Adding both areas gives a composite section that matches typical curb-and-gutter details used on roadways, parking lots, and site entries.
Segmenting runs improves field accuracy
Long alignments rarely have a single detail throughout. Returns, transitions, driveway flares, and localized thickening should be measured as separate segments. Calculate each segment volume, then sum totals. This approach reduces over‑ordering while still protecting the pour schedule. If the curb becomes rectangular in a segment, simply set top width equal to bottom width for that portion and re-run the calculation.
Waste factors and ordering strategy
A waste factor covers small overruns, spillage, trimming, and minor form irregularities. Well-controlled site pours may use 3–5%, while complex layouts or hand‑finished work may justify 6–10%. Treat the waste allowance as a planning buffer, then coordinate delivery quantities with truck capacities and placement rates so that finishing crews are not forced to retemper concrete near the end of the run.
Weight and cost checks for logistics
Converting volume to weight helps when planning equipment access, subgrade support, and material handling. Density varies with mix design and aggregate type, so use supplier data when available. A unit cost per cubic meter provides a fast budget check, useful for early estimates and bid comparisons. Final pricing should reflect admixtures, pumping, access constraints, and curing requirements.
Example data to validate inputs
Use the values below to sanity-check your workflow before entering project drawings:
| Length (m) | Top (m) | Bottom (m) | Height (m) | Gutter (m) | Thk (m) | Waste |
|---|---|---|---|---|---|---|
| 30 | 0.15 | 0.20 | 0.18 | 0.60 | 0.12 | 5% |
| 60 | 0.18 | 0.25 | 0.20 | 0.75 | 0.13 | 6% |
Confirm your section detail, then separate unusual areas into short segments for better control.
FAQs
1) What curb profile does this calculator assume?
It models the curb as a trapezoid using top width, bottom width, and height. This fits many formed curb details. If your curb is rectangular, enter the same value for top and bottom widths.
2) How is the gutter portion calculated?
The gutter is treated as a rectangular slab: width multiplied by thickness. This represents the concrete between the curb face and pavement edge for typical curb-and-gutter sections.
3) Should I include driveway flares and returns?
Yes. Treat flares, returns, and transitions as separate segments with their own dimensions and lengths. Calculate each segment and add results to avoid underestimating concrete near changes in geometry.
4) What waste factor should I use?
Use 3–5% for straightforward runs with good control. Use 6–10% for complex geometry, hand finishing, or higher site loss. Adjust based on your crew experience and supplier tolerance.
5) Why does the calculator show cubic yards and cubic feet?
Those conversions help when suppliers or crews discuss order sizes in different units. The base calculation is in cubic meters, then it converts to other units for quick cross-checking.
6) How accurate is the weight estimate?
Weight depends on mix density. The default density is typical for normal‑weight concrete, but you should enter supplier density if available. Use the weight figure for logistics planning, not structural design.
7) Can I export results for submittals or records?
Yes. After calculating, use the CSV download for spreadsheets and the PDF download for a simple shareable report. Keep the exported file with your pour ticket and daily field report.