How to use the compost carbon:nitrogen ratio calculator
Blend two materials to reach a target C:N ratio. Enter mass of material 1, c:n of material 1, mass of material 2, c:n of material 2, n content of material 1, n content of material 2 in the fields above; the mixture c:n is computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- m1 — Mass of material 1 (kg)
- c1 — C:N of material 1
- m2 — Mass of material 2 (kg)
- c2 — C:N of material 2
- n1 — N content of material 1 (%)
- n2 — N content of material 2 (%)
Worked example
With mass of material 1 = 10 kg, c:n of material 1 = 30, mass of material 2 = 5 kg, c:n of material 2 = 15, n content of material 1 = 1.5 %, n content of material 2 = 2.5 %, the calculator gives mixture c:n ≈ 23.18182.
Frequently asked questions
What is the formula for the compost carbon:nitrogen ratio calculation?
Mixture C:N = (m1 × n1 × c1+m2 × n2 × c2) / (m1 × n1+m2 × n2). Here m1 is mass of material 1 (kg), c1 is c:n of material 1, m2 is mass of material 2 (kg), c2 is c:n of material 2, n1 is n content of material 1 (%), n2 is n content of material 2 (%).
What inputs do I need for the compost carbon:nitrogen ratio calculator?
You need mass of material 1 in kg, c:n of material 1, mass of material 2 in kg, c:n of material 2, n content of material 1 in %, n content of material 2 in %. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.