Adjust unit price when the received GSM differs from the PO-agreed GSM — the garment industry's standard pro-rata on weight.
Expression
Adjusted_price_per_m = Base_price_per_m × (Actual_GSM / Agreed_GSM)Line_amount = Adjusted_price_per_m × Quantity_mVariance = (Actual_GSM − Agreed_GSM) / Agreed_GSM × 100Inputs
Rate agreed in the PO for the nominal GSM.
GSM stated in the PO line item.
Measured GSM on the received lot (from GRN).
Delivered quantity.
Output
Revised rate to invoice the buyer / pay the vendor.
Worked Example
Base_price_per_m
₹175
Agreed_GSM
200
Actual_GSM
190
Quantity_m
6,000
A 10-GSM shortfall on 6,000 m reduces the invoice by ₹52,500.
Notes
- •Most tolerant contracts waive adjustment when the variance is within the PO's GSM tolerance (typical ±5%).
- •Outside tolerance, prices are pro-rated on the actual weight — fabric is sold by weight, priced by meter.
- •Same pattern applies in reverse: over-GSM lots increase the invoice, subject to buyer approval.
Where it's Used4
Purchase Orders — Create form
GSM and its tolerance are captured on every PO line.
/purchase-orders
Quality Control — Inspection
Weight Check flags lots that exceed GSM tolerance.
/qc
GRN — Receive
Actual GSM recorded at receipt feeds the pro-rate.
/grn
Sales Invoices / Purchase Invoices
Line amount applies the adjusted price when billing.
/invoices