Define the purchasing question
Paper reel mass is useful only when the core, wrapping, moisture state and grammage basis are clear.
Normalize paper price to net mass and conditioned area, then add converter and freight charges separately. Reconcile estimated mass with a measured reel rather than treating it as certified delivery weight.
Collect measurements that match the calculation
Record weighed gross mass and independently known core and packaging tare. Use paper grammage conditioned on the same specified basis as the supplied paper. Check whether coatings are included.
Use conditioned paper grammage matching the supplied paper and coating scope. Net paper excludes core and wrapping. Moisture state and tolerances can affect real mass.
- Paper web width (mm)
- Measured paper length (m)
- Conditioned paper grammage (g/m²)
Work through an illustrative case
Net kg = Width(m) × Length(m) × Grammage/1,000
A 1 m × 1,000 m reel at 120 GSM contains 120 kg of conditioned paper.
Replace these illustrative inputs with measured data or a quotation for the same scope. Change one assumption at a time so that a difference can be traced to a dimension, quantity, charge or process change.
Avoid the expensive comparison error
Using gross weight as net paper overstates length and material purchased. Converting a tonne quote with an unconditioned or mismatched grammage introduces a second error.
- Use measured quantities and charges valid for this exact specification and period.
- Cost calculations do not qualify performance, protection or a supplier.
Common questions
What should I verify before using this result?
Record weighed gross mass and independently known core and packaging tare. Use paper grammage conditioned on the same specified basis as the supplied paper. Check whether coatings are included.
Does this calculation approve the packaging?
No. It estimates only the stated quantity, conversion or cost boundary. Technical performance and any required test or supplier approval remain separate.