| Abbreviation | Definition |
|---|---|
| HV | Heating Value |
| HV | High Voltage |
| HYE | Healthy Years Equivalent |
| HZ | Hertz |
| I | Amperage |
| IBU | International Bittering Unit |
| IBU | International Bitterness Units |
| IG | Imperial Gallon (UK) |
| Igal | Imperial Gallon (4.54609 litres) |
| IN | Inch |
| IN | Inches |
| IN.-LB | Inch Pound |
| IN² | Inches Squared |
| IN³ | Inches Cubed |
| IN-LB | Inch Pound |
| INR | International Normalized Ratio |
| INREM | INternal Roentgen Equivalent Man |
| IOC | Index Of Coincidence |
| IP | Inch-Pound |
| IPA | Instructions Per Second |