Enter lb/ft or lb/in into the calculator to convert between linear density units (US and metric options included).
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Lbs/ft to Lbs/in Formula
The calculator uses one of two formulas depending on the mode you select.
Direct conversion (lb/ft to lb/in):
lb/in = (lb/ft) / 12
Weight divided by length:
lb/in = (W / L) / 12
- lb/in = line load expressed as pounds per inch
- lb/ft = line load expressed as pounds per foot
- W = total weight in pounds
- L = spread length in feet
The factor 12 comes from 12 inches per foot. The conversion assumes the load is uniformly distributed along the length. If the load varies, this gives the average, not the peak. Other input units (kip/ft, oz/ft, kg, m, etc.) are converted to pounds and feet before the formula is applied.
Reference Values
Common conversions from lb/ft to lb/in:
| lb/ft | lb/in | oz/in |
|---|---|---|
| 1 | 0.0833 | 1.333 |
| 5 | 0.4167 | 6.667 |
| 12 | 1.000 | 16.00 |
| 24 | 2.000 | 32.00 |
| 50 | 4.167 | 66.67 |
| 100 | 8.333 | 133.3 |
| 500 | 41.67 | 666.7 |
| 1000 | 83.33 | 1333 |
Unit factors used by the calculator:
| From | To | Multiply by |
|---|---|---|
| kip/ft | lb/ft | 1000 |
| oz/ft | lb/ft | 0.0625 |
| kg | lb | 2.20462 |
| US ton | lb | 2000 |
| m | ft | 3.28084 |
| yd | ft | 3 |
Example
A beam carries a uniform load of 240 lb/ft. Convert to lb/in:
lb/in = 240 / 12 = 20 lb/in
If you only know the totals, say 1,800 lb spread evenly over 15 ft:
lb/ft = 1,800 / 15 = 120 lb/ft
lb/in = 120 / 12 = 10 lb/in
Why divide by 12? One foot equals 12 inches, so a load of X pounds per foot is the same load distributed across 12 inches. Each inch carries 1/12 of that amount.
Does this work for kip/ft? Yes. Convert kip/ft to lb/ft first by multiplying by 1,000, then divide by 12. The calculator does this automatically when you select kip/ft.
Is lb/in the same as plf or pli? plf is pounds per linear foot (lb/ft). pli is pounds per linear inch (lb/in). The conversion between them is the same divide-by-12 operation.