{
    "name": "Soil Carbon Stock Calculator",
    "url": "https://calculators.geekmidst.com/calculators/soil-carbon-stock-estimate-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/soil-carbon-stock-estimate-calculator.md",
    "category": "Agriculture",
    "description": "Estimate the organic carbon stored in a soil layer from carbon %, bulk density, depth and stone content, in tonnes C and CO₂e per hectare and field.",
    "summary": "Soil carbon stock is the mass of fine soil in the layer times its organic carbon content. Multiply by 44/12 to express it as CO₂.",
    "also_called": [
        "SOC stock calculator",
        "Soil organic carbon stock calculator"
    ],
    "applies_to": "Worldwide",
    "last_updated": "2026-10-29",
    "computation": "Results are computed in the visitor’s browser on the HTML page. This API describes the calculator; it does not compute results.",
    "inputs": [
        {
            "name": "soc",
            "label": "Soil organic carbon",
            "type": "number",
            "default": "1.2",
            "unit": "%"
        },
        {
            "name": "bulk_density",
            "label": "Bulk density",
            "type": "number",
            "default": "1.35",
            "unit": "g/cm³"
        },
        {
            "name": "depth",
            "label": "Layer depth",
            "type": "number",
            "default": "30",
            "unit": "cm"
        },
        {
            "name": "coarse",
            "label": "Stones and gravel (optional)",
            "type": "number",
            "default": "5",
            "unit": "% by volume",
            "optional": true
        },
        {
            "name": "area",
            "label": "Area",
            "type": "number",
            "default": "10"
        },
        {
            "name": "area_unit",
            "label": "Area in",
            "type": "segmented",
            "default": "ha",
            "options": {
                "ha": "Hectares",
                "acre": "Acres"
            }
        }
    ],
    "outputs": [
        {
            "key": "soc_t_ha",
            "label": "Carbon stock",
            "format": "number"
        },
        {
            "key": "co2e_t_ha",
            "label": "As CO₂ equivalent",
            "format": "number"
        },
        {
            "key": "soc_t_acre",
            "label": "Carbon stock per acre",
            "format": "number"
        },
        {
            "key": "total_c_t",
            "label": "Carbon in the area",
            "format": "number"
        },
        {
            "key": "total_co2e_t",
            "label": "CO₂ equivalent in the area",
            "format": "number"
        },
        {
            "key": "soil_mass_t_ha",
            "label": "Fine soil in the layer",
            "format": "integer"
        }
    ],
    "formula": {
        "text": "SOC stock (t C/ha) = SOC % × Bulk density (g/cm³) × Depth (cm) × (1 − Coarse fraction);  CO₂e = C × 44 ÷ 12",
        "variables": {
            "SOC %": "organic carbon by mass of fine soil",
            "Bulk density": "dry mass per volume of soil",
            "Coarse fraction": "stones and gravel share of the volume",
            "44/12": "mass ratio of CO₂ to C"
        }
    },
    "worked_example": {
        "inputs": {
            "soc": "1.2",
            "bulk_density": "1.35",
            "depth": "30",
            "coarse": "5",
            "area": "10",
            "area_unit": "ha"
        },
        "steps": [
            "Stock = 1.2 × 1.35 × 30 × 0.95 = 46.17 t C/ha.",
            "CO₂e = 46.17 × 44 ÷ 12 = 169.29 t/ha; over 10 ha, 461.7 t C."
        ],
        "result": "The top 30 cm holds about 46 t of organic carbon per hectare, equivalent to 169 t of CO₂."
    },
    "interpretation": "To compare stocks over time or between practices, sample to the same depth, or better, compare equal soil masses, because tillage and compaction change bulk density.",
    "assumptions": [
        "SOC and bulk density are averages for the whole layer."
    ],
    "limitations": [
        "A single estimate is not a verified carbon credit; carbon schemes set their own sampling and measurement rules.",
        "If you only have organic matter %, a conversion factor is needed, and it varies between soils."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "Why multiply by 44/12?",
            "answer": "A CO₂ molecule weighs 44 units and its carbon atom 12, so 1 t of carbon corresponds to 3.67 t of CO₂."
        },
        {
            "question": "Can I sum several layers?",
            "answer": "Yes. Calculate each layer with its own carbon %, bulk density and depth and add the stocks."
        }
    ],
    "sources": [],
    "related": [
        {
            "name": "Lime Application Calculator",
            "url": "https://calculators.geekmidst.com/calculators/soil-lime-requirement-calculator"
        },
        {
            "name": "Compost Volume Calculator",
            "url": "https://calculators.geekmidst.com/calculators/compost-volume-calculator"
        },
        {
            "name": "Soil Water Deficit Calculator",
            "url": "https://calculators.geekmidst.com/calculators/soil-water-deficit-calculator"
        }
    ],
    "disclaimer": null,
    "publisher": "GM¹X CalcVerse"
}