Calculate the weight of a uniform item from its length in inches and linear density in pounds per inch, or solve for length from weight.
Inches describe length and pounds describe weight or mass. They become convertible only for a particular object whose weight per unit length is known.
How to Use This Calculator
- Choose pounds from inches or inches from pounds.
- Enter the known length or weight.
- Enter linear density in lb/in.
- Calculate and review the converted customary and metric result.
After a successful calculation, the inputs and result remain saved in this browser. Select Reset to clear the stored values and restore the calculator defaults.
How the Inches to Pounds Calculator Works
Linear density is different from material density. It already includes the object’s cross-section, construction, and material, making it useful for cable, wire, extrusion, chain, and uniform stock.
The primary relationship is weight = length × linear density; length = weight ÷ linear density. Calculations retain full available precision internally; displayed values are rounded for readability.
Formula Variables and Input Guide
Enter length or weight and the item’s linear density.
| Variable or term | Meaning | Unit or note |
|---|---|---|
| L | Length | in |
| W | Weight | lb |
| d | Linear density | lb/in |
| W ÷ L | Measured linear density | lb/in |
Choosing the Right Inputs
Select whether length or weight is known, then use a linear density for the same finished item. Pounds per inch already incorporates material and cross-section; it is not the same as volumetric density in pounds per cubic inch. Remove spool, packaging, hook, and connector weight unless the specification includes those components.
Convert a datasheet value in pounds per foot to pounds per inch by dividing by 12. For a measured value, weigh a representative uniform length and divide its net pounds by its inches. Tapered stock, assemblies with repeating fittings, and products whose coating thickness changes should be divided into more uniform sections instead of being represented by one average without review.
Practical Uses
- Estimating cable or stock weight from cut length.
- Inferring remaining length from a coil weight.
- Checking shipping or inventory records.
- Converting a manufacturer linear-weight specification.
Weight of a 24-inch item
| Linear density | Weight |
|---|---|
| 0.1 lb/in | 2.4 lb |
| 0.5 lb/in | 12 lb |
| 2.0 lb/in | 48 lb |
Understanding Your Results
The result is shown in pounds and kilograms or inches and feet.
If the datasheet lists lb/ft, divide by 12 to obtain lb/in. Preserve the manufacturer’s stated tolerances when planning cut length from total weight.
Worked Example
A 24-inch item at 0.5 lb/in weighs 12 lb.
A 30 lb coil with a linear density of 0.25 lb/in contains 30 ÷ 0.25 = 120 inches, or 10 feet, of uniform product.
Checking the Result by Hand
Multiply inches by lb/in to check pounds, or divide pounds by lb/in to check inches. The unit labels provide a direct dimensional test: inches cancel in the first equation and pounds cancel in the second. A forward calculation followed by the reverse should reproduce the starting amount.
When a specification is in lb/ft, verify the conversion with a one-foot sample: its weight divided by 12 inches is the lb/in value. Doubling linear density at the same length must double calculated weight.
Common Mistakes to Avoid
- Treating inches and pounds as directly convertible units.
- Using lb/ft as though it were lb/in.
- Ignoring connectors, coatings, or packaging weight.
- Applying one value to a nonuniform or tapered product.
Assumptions and Limitations
Inches and pounds are not directly convertible. The item must have a known, reasonably uniform linear density.
Frequently Asked Questions
Can inches directly convert to pounds?
No. A specific linear density is required.
Can I use lb per foot?
Convert it to lb/in by dividing by 12.
How can I measure linear density?
Weigh a representative length and divide weight by length.
How is this different from a metal-weight calculator?
A metal calculator derives linear weight from geometry and volumetric density.