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Core Weight Calculator

Estimate the mass of a hollow cylindrical roll core from its outside diameter, inside diameter, length and density. All dimensions are converted to metres before calculating volume.

Use a saved product specification (optional)
01 / INPUTS

Enter your values

First time using this calculator?

Replace the example values with figures from your supplier sheet or measurements. Choose the unit beside each value. Results update as you type; fix any highlighted field before using the result.

GSM means grams per square metre. Net weight excludes the core and other packaging. MOQ means the minimum order quantity. An optional field can stay blank unless the result you need depends on it.

Prices keep the selected currency; changing its label does not convert an exchange rate. Save or export the result after checking your inputs.

kg/m³

700 kg/m³ is an illustrative paperboard estimate. Enter the actual core density; this is not a universal value.

Help with core material density

Density is material mass per unit volume. A typical preset is suitable for an early estimate; use the supplier grade value for purchasing decisions.

Results update as you edit. Nothing is saved until you choose to.
02 / RESULTExample result — replace the inputs

Estimated core weight

1.022 kg
Core wall volume0.001460 m³

The default density is an illustrative paperboard estimate, not a universal specification. Enter actual density or use measured core weight.

Assumes a uniform hollow cylinder; excludes plugs and end fittings.

THE CALCULATION

Core weight = π/4 × (OD² − ID²) × width × density; dimensions in m

π/4 × (0.09² − 0.076²) × 0.8 × 700 = 1.022148586 kg
Example result — replace the sample valuesThe formula works, but the values are illustrative.

Saved calculations stay in this browser. No account or cloud backup is created.

Save to a product project (optional)Choose or create a saved product project ↗

This is an illustrative example. Saved or transferred values must be checked against your job.

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Calculated from your inputs. Confirm specifications with your supplier.

How sensitive is this result to your assumptions?

Vary one input and inspect estimated core weight

All other entered inputs stay fixed. Ranges are your scenarios, not statistical confidence or supplier performance predictions. This uses the same validated calculator engine.

UNDERSTAND THE CALCULATION

The formula, made clear.

Core mass = π ÷ 4 × (OD² − ID²) × Core length × Density (kg/m³)

The difference between the outer and inner circle areas is the core wall cross-section. Multiplying it by the axial length gives solid wall volume, which is multiplied by material density to obtain kilograms. Core length is the physical tube length, which may extend beyond film width. A default paperboard density is only an estimate and must remain editable; it is not a universal value for every core construction.

How to use this calculator

  1. 01

    Measure core outside diameter, bore diameter and physical axial length.

  2. 02

    Enter material density in kilograms per cubic metre or retain a clearly identified estimate.

  3. 03

    Compare the estimated tare with a weighed sample when accurate net film accounting matters.

WORKED EXAMPLE

A calculation you can check

The example calculates the annular wall volume of a roll core and converts that volume into an estimated tare mass.

Core outside diameter
90 mm
Core inside diameter
76 mm
Core width
800 mm
Core material density
700 kg/m³
π/4 × (0.09² − 0.076²) × 0.8 × 700 = 1.022148586 kg
Estimated core weight1.022 kg
HOW TO VERIFY THIS RESULT

Check the displayed formula and units against your quotation. Use measured GSM, net weight and actual layout dimensions where available. Default densities are planning assumptions, not certified material properties. Calculated cost does not certify strength, compatibility or safe loading.

Method, units and material assumptions ↗