Thickness Converter — Inches, Millimetres and Centimetres
Specifications quote thickness in inches in North America and millimetres almost everywhere else. 2 inches is 50.8 mm; the common metric equivalent specified is 50 mm.
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Type into any field and the others update instantly.
Common paving thicknesses
| Application | Imperial | Metric |
|---|---|---|
| Thin overlay | 1" | 25 mm |
| Standard surface course | 1.5–2" | 40–50 mm |
| Residential driveway | 2–3" | 50–75 mm |
| Binder course | 2–3" | 50–80 mm |
| Parking lot | 3–6" | 75–150 mm |
| Municipal road | 6–8" | 150–200 mm |
| Highway | 8–12" | 200–300 mm |
| Aggregate base | 4–12" | 100–300 mm |
Formulas
mm = inches × 25.4
inches = mm ÷ 25.4
cm = mm ÷ 10
feet = inches ÷ 12
inches = mm ÷ 25.4
cm = mm ÷ 10
feet = inches ÷ 12
Full calculator
If you need tonnage rather than a unit conversion, use the full calculator — it applies your mix density and returns every unit at once.
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