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Carbon Price Exposure Calculator

Carbon pricing, whether a tax or a cap and trade scheme, turns emissions into a cost line. This calculator shows the annual exposure, what remains after pass-through, and a multi-year total with falling emissions.

Your numbers

Annual emissions

tCO2e

Share covered by the scheme

80 %

Many schemes cover direct emissions only; some also cover purchased electricity.

Free allocation or exemption

20 %

Share of covered emissions that need no allowance.

Carbon price

$/tCO2e

Cost passed on to customers

30 %

Annual revenue

Yearly emissions reduction

Horizon

5 years

Your results

Net cost after pass-through

$322,560

Cumulative gross cost over horizon

$2,126,907

Emissions needing allowances

7,680

Tonnes of CO2e that carry a cost.

Gross annual carbon cost

$460,800

Net cost as share of revenue

0.4032

Shown in percent.

Declining sum factor

4.6157

Sum of yearly emission ratios over the horizon.

Illustrative model. Scheme scope, allocation rules and price paths differ by jurisdiction. Confirm with the regulator or legal counsel.

Save results:

Cost vs carbon price

Sweeps Carbon price from 0 to 200, holding your other inputs fixed.

Need carbon cost in your ERP reports?

Optional expert review of linking emissions inventory data to finance reporting.

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

How to use the calculator

Start from your inventory: total tCO2e and the share the scheme covers. Enter free allocation or exemption as a percentage of covered emissions, then a carbon price. Pass-through is the share of the cost you recover from customers through surcharges or price increases. Revenue lets the model show carbon cost as a share of sales, a common board metric. Set a yearly reduction and horizon to see the cumulative effect of decarbonizing while the price applies.

Run a low, base and high price case
Use the price sweep chart to find your break-even for abatement projects
Separate Scope 1 and Scope 2 runs if coverage differs

The math

Billable tonnes equal emissions times coverage times one minus free allocation. Gross cost is billable tonnes times price, and net cost applies the pass-through share. For the horizon, emissions fall by a constant yearly percentage, so year k costs gross times (1 - r) to the power k-1. The sum of that geometric series is (1 - (1 - r)^n) divided by r, which is the declining sum factor shown. When r is zero the factor simply equals the number of years.

Using the result for decisions

An internal or shadow carbon price is useful even where no scheme applies. Compare your net cost per tonne with the marginal abatement cost of projects such as leak repair, boiler tune-ups or heat recovery. Any project whose cost per tonne avoided is below the carbon price improves the financial case. Finance can treat the cumulative figure as a risk reserve, and customers in regulated supply chains may ask for the same number in tenders.

Common mistakes

Do not apply the price to Scope 3 unless the scheme explicitly covers it. Do not assume free allocation stays constant; many schemes phase it down. Prices are often quoted per tonne of CO2, not CO2e, so check which gases are included. Keep the assumptions and the version of the inventory in your reporting system so the exposure can be reproduced at audit.

Check gas coverage
Check allocation phase-out dates
Record the price source and date

Frequently Asked Questions

What is the difference between a carbon tax and an ETS here?

A tax sets the price and the volume floats; an emissions trading scheme caps volume and the price floats. For this model both reduce to a price per tonne on billable emissions, so you can test either with a price range.

What does free allocation mean?

Regulators may give allowances to some sectors at no charge, or exempt part of emissions. Enter that share as a percentage of covered emissions. Only the remainder needs to be bought or paid as tax.

Why does the cumulative figure use declining emissions?

If you invest in reductions, each later year costs less. The geometric series captures a constant percentage cut. Set the reduction to zero for a flat profile to see the unmitigated exposure.

Can I use it as an internal carbon price?

Yes. Set coverage to 100 percent, free allocation to zero and enter a shadow price. The result is a budget line you can charge to business units or use to rank abatement projects.

Netray can connect energy, fuel and production data in your ERP to a repeatable emissions and carbon cost view that stays on your own infrastructure.

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