Tá 1 orlach cothrom le 25.4 milliméadar:
1 ″ = 25.4mm
Tá an fad d i milliméadair (mm) cothrom leis an bhfad d in orlach (″) uaireanta 25.4:
d (mm) = d (″) × 25.4
Tiontaigh 20 orlach go milliméadar:
d (mm) = 20 ″ × 25.4 = 508mm
| Inches (") | Milliméadar (mm) | 
|---|---|
| 0.01 ″ | 0.254000 mm | 
| 1/64 ″ | 0.396875 mm | 
| 1/32 ″ | 0.793750 mm | 
| 1/16 ″ | 1.587500 mm | 
| 0.1 ″ | 2.540000 mm | 
| 1/8 ″ | 3.175 mm | 
| 1/4 ″ | 6.35 mm | 
| 1/2 ″ | 12.7 mm | 
| 1 ″ | 25.4 mm | 
| 2 ″ | 50.8 mm | 
| 3 ″ | 76.2 mm | 
| 4 ″ | 101.6 mm | 
| 5 ″ | 127.0 mm | 
| 6 ″ | 152.4 mm | 
| 7 ″ | 177.8 mm | 
| 8 ″ | 203.2 mm | 
| 9 ″ | 228.6 mm | 
| 10 ″ | 254.0 mm | 
| 20 ″ | 508.0 mm | 
| 30 ″ | 762.0 mm | 
| 40 ″ | 1016.0 mm | 
| 50 ″ | 1270.0 mm | 
| 60 ″ | 1524.0 mm | 
| 70 ″ | 1778.0 mm | 
| 80 ″ | 2032.0 mm | 
| 90 ″ | 2286.0 mm | 
| 100 ″ | 2540.0 mm |