Free Tool · Architects & Designers
Unit Converter for Architects and Designers
Convert between mm, cm, m, inches, and feet instantly. Free metric-imperial unit converter for architects, interior designers, and product designers. No sign-up required.
Enter a value above to see all conversions.
Click a unit to set it as the input unit:
Common Architectural Dimensions
Metric and imperial standards are not just conversions of each other — they are independently established norms. Both tables are shown separately so you can see the actual standards used in each system.
Metric System
| Dimension | mm | cm | m | in | ft–in |
|---|---|---|---|---|---|
| Standard door height Typical residential interior door | 2100 | 210 | 2.1 | 82.7 | 6′10.7″ |
| Standard ceiling height Minimum comfortable ceiling height | 2400 | 240 | 2.4 | 94.5 | 7′10.5″ |
| Standard door width Single hinged door, residential | 900 | 90 | 0.9 | 35.4 | 2′11.4″ |
| Stair riser height Standard comfortable step rise | 180 | 18 | 0.18 | 7.1 | 0′7.1″ |
| Stair tread depth Minimum comfortable tread depth | 280 | 28 | 0.28 | 11 | 0′11″ |
| Kitchen counter height Standard worktop height | 900 | 90 | 0.9 | 35.4 | 2′11.4″ |
| Typical room width Minimum comfortable bedroom width | 3600 | 360 | 3.6 | 141.7 | 11′9.7″ |
| Standard brick length Standard EU/UK metric brick | 215 | 21.5 | 0.215 | 8.5 | 0′8.5″ |
Imperial System
| Dimension | ft–in | in | mm | cm | m |
|---|---|---|---|---|---|
| Standard door height Standard North American interior door | 6′8″ | 80 | 2032 | 203.2 | 2.032 |
| Standard ceiling height Typical residential floor-to-ceiling | 8′0″ | 96 | 2438 | 243.8 | 2.438 |
| Standard door width Standard residential interior door | 2′8″ | 32 | 813 | 81.3 | 0.813 |
| Stair riser height Typical comfortable step rise | 7″ | 7 | 178 | 17.8 | 0.178 |
| Stair tread depth Typical comfortable tread depth | 11″ | 11 | 279 | 27.9 | 0.279 |
| Kitchen counter height Standard US countertop height | 3′0″ | 36 | 914 | 91.4 | 0.914 |
| Typical room width Minimum comfortable bedroom width | 10′0″ | 120 | 3048 | 304.8 | 3.048 |
| Standard brick length Standard US modular brick | 7⅝″ | 7.625 | 194 | 19.4 | 0.194 |
Frequently Asked Questions
About unit conversion for architects and designers
- Divide millimeters by 25.4 to get inches. For example, 100mm ÷ 25.4 = 3.937 inches. Alternatively, multiply by 0.03937. This converter does it automatically — enter your value in mm and see the inch equivalent instantly.
- There are exactly 304.8 millimeters in one foot. One foot equals 12 inches, and one inch equals 25.4mm, so 12 × 25.4 = 304.8mm. This is a key conversion for architects working between metric and imperial systems.
- Most countries use metric units — millimeters (mm) and meters (m) are the standard in architecture. The UK uses a mix of metric and imperial. The USA primarily uses feet and inches. When sharing drawings internationally or specifying imported fixtures and materials, unit conversion is essential.
- Multiply feet by 30.48 and inches by 2.54, then add the results. For example, 6 feet 2 inches = (6 × 30.48) + (2 × 2.54) = 182.88 + 5.08 = 187.96 cm. This converter handles single-unit conversions — enter feet as a decimal (e.g., 6.167 ft for 6 ft 2 in).
- Architectural projects frequently involve both metric and imperial measurements in the same workflow — client briefs, imported building products, international standards, and legacy drawings may all use different unit systems. Quick, accurate conversion prevents costly errors in drawings and specifications.
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