How do you calculate resin price variance?

Multiply the affected resin weight by the price difference per unit and your allocation share, then add fixed adjustments. For 18,000 kg at a $0.32/kg delta fully allocated plus a $1,200 freight variance: 18,000 × 0.32 × 100% = $5,760, plus $1,200 = $6,960 total.

What does a positive resin price variance mean?

A positive number is an unfavorable variance — you paid more than standard. The example's $6,960 means this bio-resin purchase cost $6,960 above budget once the price delta and freight surcharge are combined.

What is the variance allocation share for?

It is the percentage of the price delta you are charging to this cost center, job, or period. At 100% the full delta lands here; set it lower to split a shared purchase across multiple jobs or to defer part of the variance.

How is price variance different from purchase price variance per unit?

The total is the dollar impact; the per-unit figure normalizes it. Here the $6,960 total works out to about $0.387 per kg across the 18,000 kg — higher than the raw $0.32 delta because the fixed $1,200 freight variance spreads over the same weight.

Should freight surcharges go in price variance?

If the surcharge is tied to that resin purchase and not in your standard cost, yes — enter it as fixed supplier or freight variance. Keeping it separate from the per-kg delta lets you see how much of the overage is market-driven versus logistics.

Bioplastics & Biomaterials Processing calculator

Resin Price Variance Calculator

Resin price variance is the dollar gap between what you actually paid for bio-resin and your standard or budgeted price, scaled across the volume purchased. Cost accountants, purchasing managers, and plant controllers track it because bio-feedstock prices (PLA, PHA, bio-PE) swing with crop yields, oil parity, and supply contracts far more than commodity resins. Isolating the variance — and splitting the variable price effect from fixed supplier or freight surcharges — tells you whether margin erosion came from the market or from a one-time logistics hit. This calculator returns the total variance and the effective variance per weight unit.

What this calculator does

Estimate cost exposure from a PLA, PHA, PBAT, PBS, starch blend, or bio-compound price variance across a planned material volume.
a materials buyer or estimator needs to quantify the impact of a bio-resin price increase, decrease, or supplier quote variance
It computes the total unfavorable or favorable resin price variance by multiplying affected weight by the per-unit price delta and allocation share, then adding any fixed supplier or freight variance.

Formula used

Allocated variable resin variance = affected bio-resin weight × resin price variance × variance allocation share
Total resin price variance = allocated variable resin variance + fixed supplier or freight variance

Inputs explained

Affected bio-resin weight:
Resin price variance:
Variance allocation share:
Fixed supplier or freight variance:

How to use the result

Use it at month-end cost analysis, during a price-increase notification from a supplier, or when investigating why a bio-resin job came in over standard cost.
It captures price variance only; it does not isolate usage or yield variance, so a job that also overconsumed resin will need a separate quantity-variance calculation.

Current U.S. benchmarks

The producer price index for plastic resins and materials stands at 319.371 (BLS, May 2026), up 19.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.

Common questions

How do you calculate resin price variance? Multiply the affected resin weight by the price difference per unit and your allocation share, then add fixed adjustments. For 18,000 kg at a $0.32/kg delta fully allocated plus a $1,200 freight variance: 18,000 × 0.32 × 100% = $5,760, plus $1,200 = $6,960 total.
What does a positive resin price variance mean? A positive number is an unfavorable variance — you paid more than standard. The example's $6,960 means this bio-resin purchase cost $6,960 above budget once the price delta and freight surcharge are combined.
What is the variance allocation share for? It is the percentage of the price delta you are charging to this cost center, job, or period. At 100% the full delta lands here; set it lower to split a shared purchase across multiple jobs or to defer part of the variance.
How is price variance different from purchase price variance per unit? The total is the dollar impact; the per-unit figure normalizes it. Here the $6,960 total works out to about $0.387 per kg across the 18,000 kg — higher than the raw $0.32 delta because the fixed $1,200 freight variance spreads over the same weight.
Should freight surcharges go in price variance? If the surcharge is tied to that resin purchase and not in your standard cost, yes — enter it as fixed supplier or freight variance. Keeping it separate from the per-kg delta lets you see how much of the overage is market-driven versus logistics.

Last reviewed 2026-05-12.