Calculate the initial foot-pounds per inch value. Once you've measure the starting figure, you'll be able to convert with great ease.
Multiply your original amount by 53.38. There are 53.38 (rounded to the hundredth) joules per meter in each foot-pound per inch. This number should give you an approximation. If you need a more specific figure, multiply by 53.3786594.
Relabel the unit of measurement to joules per meter. Your resulting amount should be accurate to the nearest hundredth, unless you used the extended decimal places for increased accuracy.