Net Zero Calculator Formula
Understand the math behind the net zero calculator. Each variable explained with a worked example.
Formulas Used
Residual Emissions at Target
residual_emissions = residualTotal Reduction Achieved
reduction_achieved = total_reducedAnnual Offsets Needed
offset_needed = residualAnnual Offset Cost
offset_cost = residual * offset_priceVariables
| Variable | Description | Default |
|---|---|---|
current_emissions | Current Annual Emissions(metric tons CO2e) | 1000 |
reduction_pct | Annual Reduction Rate(%) | 7 |
target_year | Years to Net Zero(years) | 10 |
offset_price | Offset Price per Ton(USD) | 30 |
residual | Derived value= current_emissions * pow(1 - reduction_pct / 100, target_year) | calculated |
total_reduced | Derived value= current_emissions - residual | calculated |
How It Works
How to Plan for Net Zero
Net zero means reducing emissions as much as possible and offsetting the remainder.
Formula
Residual Emissions = Current * (1 - Annual Reduction %)^Years
Offsets Needed = Residual Emissions
The Science Based Targets initiative requires at least 90% absolute reduction before relying on offsets for net zero. Remaining emissions must be neutralized through high-quality carbon removal.
Worked Example
A company emitting 1,000 tons CO2e reduces 7% annually over 10 years with $30/ton offsets.
- 01Residual: 1,000 * (1 - 0.07)^10 = 1,000 * 0.484 = 484 metric tons
- 02Total reduced: 1,000 - 484 = 516 metric tons
- 03Offsets needed: 484 metric tons/year
- 04Offset cost: 484 * $30 = $14,520/year
Frequently Asked Questions
What does net zero mean?
Net zero means that any greenhouse gases emitted are balanced by an equivalent amount removed from the atmosphere, resulting in no net increase in atmospheric CO2.
What reduction rate is needed for 2050 net zero?
To reach net zero by 2050 from current levels requires roughly 7-10% annual emission reductions, depending on starting point and how much residual can be offset.
What counts as a valid offset for net zero?
For SBTi net zero, only carbon removal offsets count (direct air capture, enhanced weathering, afforestation). Avoidance credits do not qualify for neutralizing residual emissions.
Ready to run the numbers?
Open Net Zero Calculator