Minimum breaking strength, safe load, and weight for standard polyester ropes. Safe load calculated with a safety factor of 12.
Diameter(in)	Diameter(mm)	Min. Breaking Strength(lbf)	Min. Breaking Strength(kN)	Safe Load (SF 12)(lbf)	Safe Load (SF 12)(kN)	Weight(lbm/ft)	Weight(kg/m)
3/16	5	765	3.4	63.8	0.284	0.011	0.016
1/4	6	1315	5.85	110	0.487	0.02	0.029
5/16	8	2050	9.1	171	0.76	0.031	0.045
3/8	10	2900	12.9	242	1.07	0.044	0.065
7/16	11	3915	17.4	326	1.45	0.059	0.088
1/2	12	5085	22.6	424	1.88	0.077	0.115
9/16	14	6435	28.6	536	2.39	0.098	0.146
5/8	16	7825	34.8	652	2.9	0.12	0.179
3/4	18	11200	49.8	933	4.15	0.172	0.256
7/8	22	15225	67.7	1270	5.65	0.234	0.348
1	24	19775	88	1650	7.34	0.304	0.452
1 1/16	26	22225	99	1850	8.23	0.342	0.509
1 1/8	28	24800	110	2070	9.21	0.385	0.573
1 1/4	30	29800	133	2480	11	0.465	0.692
1 3/8	32	32500	145	2710	12.1	0.465	0.759
1 1/2	36	42200	188	3520	15.7	0.51	0.997
1 5/8	40	49250	219	4100	18.2	0.67	1.16
1 3/4	44	57000	254	4750	21.1	0.78	1.35
2	48	72000	320	6000	26.7	0.91	1.74

Source: engineeringtoolbox.com

Additional Formula: Mass from Safe Load

The safe working load can be converted to an equivalent mass using Newton's second law.

$m = \frac{F}{g}$

Where:

Example Calculation for a 3/8" Rope: Given a safe load $F = 1.07 \, \text{kN} = 1070 \, \text{N}$ :

$m = \frac{1070 \, \text{N}}{9.81 \, \text{m/s}^2} \approx 109 \, \text{kg}$

This means a 3/8" polyester rope can safely support a static mass of approximately 109 kg.

Polyester Rope Strength