How to use this calculator
  1. Base Input
    • Enter Biochar application costs.
    • Establish a gross margin: grain price, yield and expected change in income (%) due to biochar use.
    • c. Limiting factors: only ph has been entered to date (If you enter a ph above 6, then the program will show no benefit / saving to liming).
  2. Additional Factors (changes to nutrient/lime requirements etc.):
    • Enter any expected changes in proposed N, P, K and lime requirements. (This section is very subjective and designed for testing ideas, not to be used to provide a prescription.)
  3. Impact of Biochar:
    • This measures how much of the improvement in profit can be expected to flow after year 1. The second part of the calculation is to make judgement on how many years it is feasible to apply the altered level of nutrients. The base assumptions for the model assume a cost saving on inputs of $8.35/ha for 4 years after the application of Biochar. Please change this to suit your own property.
    • If you believe Biochar effects are nil in less than the five years, enter a “0%” in the years you believe there is no benefit, and an “n” in the same years in the column asking whether to apply input changes.
  4. Summary – This deducts the cost of the treatment from the benefit expected over five years to assess whether the treatment is considered worth pursuing base on the estimates you have made.
Base Inputs
Application Rate (t/ha)
Costs Product ($/t)
Transport ($/t)
Application ($/t)
Total Cost Per t applied $150.00
Total cost of Biochar per Ha applied $150.00
Change in Crop Gross Margin
On Farm Grain Price ($/t)
Average Yield ((t/ha)
Total Income $500.00
Expected Change in Yield
Improvement in crop gross margin ($/ha) $50.00
Factor Limiting Saving
Initial Soil pH
Only pH below 6 shows a benefit to lime req

Additional Factors

Kg $/t landed and applied $/ha increase in cost
Change in N Requirements
Change in P Requirements
Change in K Requirements
Change in Lime Requirements
Change In Inputs -$8.35

Impact of Biochar over 5 Years

Cost of Funds
Improvment in
Gross Margin
Benefit Apply input
Changes in
Net Benefit
Year 1
-$8.35 $58.35
Year 2
-$8.35 $48.35
Year 3
-$8.35 $38.35
Year 4
-$8.35 $28.35
Year 5
-$8.35 $0.00
Total Value of Changes to Income $146.76

Summary of Outcome

Total Biochar Outlay ($ / ha) $150.00
Present value of change in income ($/ha) $146.76
Net Benefit ($ / ha) -$3.24

The aim of the biochar calculator is to allow farmers to test the economic impact of Biochar on their existing returns and to test the effect of changing each of their assumptions. It is intended as a means of assessing potential financial benefits of applying biochar as a soil ameliorant.

The calculator assumes that biochar is added once with benefits extending up to five years, and requires you to estimate values of key inputs and perceived outcomes.