Supply Chain & InventoryFree calculatorPDF, Excel, Word export

Commodity Index Price Adjustment Clause Calculator

Index-linked contracts move price with a published metal, resin or energy index. This calculator shows what a given index movement does to the price of one part under a dead band and a partial pass-through.

Your numbers

$
45 %

Portion of the price that is the indexed raw material.

Index level when the price was agreed.

112

Published index for the adjustment period.

100 %

Some clauses index only part of the material cost.

%

Index must move more than this before the price changes.

units

Your results

Price adjustment per unit
$1
Adjusted unit price
$19
Index change
12%
Adjustment triggered (1 = yes)
1
Price change
5.4%
Annual cost impact
$39,960

Illustrates a common structure only. Your contract may adjust on the excess beyond the band, use averages or lags, and cap increases. Follow the contract wording.

Save results:

Unit price adjustment vs current index

Sweeps Current index value from 60 to 160, holding your other inputs fixed.

Index-linked price updates in your ERP

Optional: we can discuss controlled, approval-based price list updates driven by published indices.

Optional. The tool and every export work without this. No spam.

How to use it

Enter the contract price, the share of that price that is the indexed material, and the base and current index values. Set the dead band, which is the move the index must exceed before any adjustment applies, and the share of the material that is indexed. The tool returns the index change, the adjusted unit price and the annual cost impact. Sweep the current index in the chart to see the full price curve, including the flat zone inside the band.

The formula

Adjustment per unit equals base price times material share times the index change times the indexed share, applied only when the absolute change exceeds the band. A 45 percent material share on an 18.50 part means 8.33 of the price is exposed. A 12 percent index rise with a 5 percent band then adds about 1.00 per unit. Some clauses adjust only on the amount beyond the band, which would lower this figure.

  • Exposed cost = price x material share
  • Index change = current / base - 1
  • Adjustment triggers only outside the dead band
  • Annual impact = adjustment x volume

Reading the result

The percent change in part price is always smaller than the index move because only part of the price is material. Use that ratio to decide whether to negotiate a narrower band, a cap, or a fixed-price period. Buyers dislike one-way clauses, so check that the same formula applies when the index falls. Compare the annual impact with the price premium a supplier would want for fixed pricing to see which is cheaper over a cycle.

Common mistakes

Common errors are using the wrong index unit, such as dollars per tonne versus a cents per pound series, or mixing a lagged index with a spot price. Make sure the base index date matches the quote date. If the supplier buys in a different currency or region, a regional premium may matter more than the headline index. In ERPs, record the index and formula on the price agreement so the price update is traceable.

Frequently Asked Questions

What is a dead band?

A range around the base index inside which no price change occurs. It prevents constant small adjustments and shares the risk of minor volatility between buyer and supplier.

Should the clause work both ways?

Yes. A balanced clause adjusts down when the index falls, using the same formula. One-way clauses that only allow increases should be negotiated or priced accordingly.

How often should prices adjust?

Monthly or quarterly is common, often using an average of the prior period to reduce noise. Faster adjustment tracks cost more closely but adds administrative load.

Which index should I choose?

Pick a published index that matches what the supplier actually buys and that both sides can verify, such as an exchange or industry price series for the grade and region.

If you want index-linked prices updated and checked against purchase orders in your ERP, Netray can build a controlled workflow with human approval.

Talk to an ExpertExplore More Free Tools

Related Tools

Costing & Finance

Supplier Price Increase Impact Calculator

Sizes the annual cost of a requested price increase and compares it with the increase justified by a material index.

Supply Chain & Inventory

Supplier Price Increase Response Letter Template

A firm, professional reply to a supplier asking for a price rise, requesting cost evidence and proposing a counter.

Supply Chain & Inventory

Dual Source Split Award Cost and Risk Calculator

Test whether splitting volume with a second supplier pays for itself once price premium, qualification cost and expected disruption losses are counted.

Costing & Finance

Supplier Cost Savings Tracker Worksheet

Track negotiated savings by item and initiative, with annual value, percent saved and a hard versus soft split, ready to export to Excel.

More Supply Chain & Inventory tools

See all
Back to All Tools