25 Nm = 18.44 ft-lbs
That is 18.44 lb-ft, 221.3 in-lb or 254.9 kg-cm.
Spark plugs (14 mm, flat seat with a washer) in aluminium heads are typically 25 to 30 Nm. It is close to the typical dry torque for M8 grade 8.8 (25 Nm). See the metric bolt torque chart. Always use the figure in your vehicle or part maker's manual.
Multiply Nm by 0.737562: 25 x 0.737562 = 18.44 ft-lbs. To go back, multiply ft-lbs by 1.35582. On a torque wrench, set 18 ft-lbs (or 221 in-lb on a small wrench).
| Nm | ft-lbs | in-lb |
|---|---|---|
| 20 | 14.75 | 177.0 |
| 21 | 15.49 | 185.9 |
| 22 | 16.23 | 194.7 |
| 23 | 16.96 | 203.6 |
| 24 | 17.70 | 212.4 |
| 25 | 18.44 | 221.3 |
| 26 | 19.18 | 230.1 |
| 27 | 19.91 | 239.0 |
| 28 | 20.65 | 247.8 |
| 29 | 21.39 | 256.7 |
| 30 | 22.13 | 265.5 |
Full list: Nm to ft-lbs chart (1 to 300 Nm). Going the other way: ft-lbs to Nm chart.
Built and maintained by Daryn Potgieter. Conversion factor from NIST SP 811. Last reviewed 28 September 2026. Spotted an error? Tell us.