What is the difference between torque and energy?

Both share the same SI unit (N·m) but are conceptually different. Torque is rotational force; energy/work is force through a linear distance.

How do I convert ft·lb to N·m?

Multiply foot-pounds by 1.35582. Example: 100 ft·lb × 1.35582 = 135.58 N·m.

Convert between newton-meters, foot-pounds, inch-pounds, and kilogram-force meters.

Newton-meter

N·m

Kilonewton-meter

kN·m

Foot-pound

ft·lb

Inch-pound

in·lb

Inch-ounce

in·oz

Kilogram-force meter

kgf·m

Torque (moment of force) measures the rotational force around an axis.