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Power and Energy

ft·lbftoJ

Convert foot-pounds force (ft·lbf) to joules (J).

Factor1 ft·lbf = 1.355818 J

Converter

ft·lbf

Accepts numbers or expressions, e.g. 150 + 14.7

Result
135.582J

Rendered to 6 significant figures.

Formula

Formula
J = ft·lbf × 1.355818

Multiply any value in foot-pounds force by 1.355818 to obtain the value in joules.

Worked example

Convert 100 ft·lbf to J.

  1. 01Start with 100 ft·lbf.
  2. 02Multiply by the conversion factor: 100 × 1.355818 = 135.582 J.
Result100 ft·lbf = 135.582 J

Conversion table

ft·lbfJ
11.3558
22.7116
56.7791
1013.558
2027.116
5067.791
100135.58
200271.16
500677.91
10001355.8

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from ft·lbf to J?
1 ft·lbf equals 1.355818 J. To convert, multiply the value in foot-pounds force by 1.355818.
How do I convert 1 ft·lbf to J?
1 ft·lbf = 1.35582 J. For any value, multiply by 1.355818.
How do I convert J back to ft·lbf?
Divide by the same factor — or equivalently, multiply by 0.7375621. So 1 J = 0.737562 ft·lbf.
When would I need to convert foot-pound force to joule?
Energy conversions are needed when reconciling fuel/electrical billing, calculating thermal duties, and aligning calorimetry or HHV/LHV figures across data sources.
Is the conversion exact?
The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).

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