LBM To LBF Conversion Calculator – Convert Pound-Mass to Pound-Force

Our pound-mass (lbm) to pound-force (lbf) calculator is designed for converting between mass and force units.

A rocket component weighing 100 lbm on Earth. Using the calculator, engineers can determine that this translates to approximately 100 lbf under Earth’s gravity. But, on Mars (with roughly 38% of Earth’s gravity), the same 100 lbm mass would exert only about 38 lbf of force.

LBM To LBF Conversion Chart

LBM (Pound-Mass) Converted to	LBF (Pound-Force)
1	1.000
2	2.000
3	3.000
4	4.000
5	5.000
6	6.000
7	7.000
8	8.000
9	9.000
10	10.000
11	11.000
12	12.000
13	13.000
14	14.000
15	15.000
16	16.000
17	17.000
18	18.000
19	19.000
20	20.000
21	21.000
22	22.000
23	23.000
24	24.000
25	25.000
26	26.000
27	27.000
28	28.000
29	29.000
30	30.000
31	31.000
32	32.000
33	33.000
34	34.000
35	35.000
36	36.000
37	37.000
38	38.000
39	39.000
40	40.000
41	41.000
42	42.000
43	43.000
44	44.000
45	45.000
46	46.000
47	47.000
48	48.000
49	49.000
50	50.000
100	100.000
200	200.000
500	500.000

LBM to LBF Conversion Formula

The relationship between mass and force is defined by Newton’s Second Law: F = ma. For Earth-based calculations, the formula specifically becomes:

LBF = LBM × (32.174 × gravity)

Where:

• LBM: Pounds Mass
• LBF: Pounds Force
• Gravity: Gravitational acceleration in feet per second squared (ft/s²).

LBF = 200 × (32.174/32.174)
LBF = 200 × 1
LBF = 200 lbf

How to Convert lb force to lb mass

To convert pound-force back to pound-mass, simply divide by the gravitational factor:

LBM = LBF × (gc/g)

A force of 75 lbf converts to mass:

LBM = 75 × (32.174/32.174)
LBM = 75 × 1
LBM = 75 lbm

For these conversions, we’ll assume standard Earth gravity (32.174 ft/s²)

• 150 lbm person → 150 lbf
• 2000 lbm vehicle → 2000 lbf
• 0.5 lbm smartphone → 0.5 lbf
• 750 lbm motorcycle → 750 lbf
• 25 lbm dumbbell → 25 lbf

What is LBM and LBF?

Pound-mass (lbm) represents the quantity of matter in an object, remaining constant regardless of location. Like kilograms, it’s a true mass unit used in engineering calculations, particularly in the US customary system.

Pound-force (lbf) measures the gravitational force exerted on a mass, varying with gravitational field strength. It’s commonly used in structural engineering, aerospace, and mechanical design to calculate loads, stresses, and material requirements.