{
    "name": "Hydroponic Nutrient Concentration Calculator",
    "url": "https://calculators.geekmidst.com/calculators/hydroponic-nutrient-concentration-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/hydroponic-nutrient-concentration-calculator.md",
    "category": "Agriculture",
    "description": "Find the grams of fertiliser to dissolve for a target ppm of nitrogen, phosphorus, potassium or another nutrient, with P₂O₅ and K₂O label conversion.",
    "summary": "One ppm in water is one milligram per litre. Multiply the target ppm by the reservoir volume, then divide by the nutrient share of the fertiliser.",
    "also_called": [
        "Nutrient solution calculator",
        "Fertigation ppm 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": "target_ppm",
            "label": "Target concentration of the nutrient",
            "type": "number",
            "default": "200",
            "unit": "ppm (mg/L)"
        },
        {
            "name": "content",
            "label": "Nutrient content on the fertiliser label",
            "type": "number",
            "default": "15.5",
            "unit": "%"
        },
        {
            "name": "label_form",
            "label": "Label states the nutrient as",
            "type": "select",
            "default": "element",
            "options": {
                "element": "Element (N, P, K, Ca, Mg…)",
                "p2o5": "P₂O₅ (phosphate)",
                "k2o": "K₂O (potash)"
            }
        },
        {
            "name": "volume",
            "label": "Reservoir or tank volume",
            "type": "number",
            "default": "100"
        },
        {
            "name": "volume_unit",
            "label": "Volume in",
            "type": "segmented",
            "default": "l",
            "options": {
                "l": "Litres",
                "us_gal": "US gallons"
            }
        },
        {
            "name": "stock_ratio",
            "label": "Stock solution concentration",
            "type": "number",
            "default": "100",
            "unit": "× (e.g. 100 for 1:100)",
            "optional": true
        }
    ],
    "outputs": [
        {
            "key": "grams",
            "label": "Fertiliser to dissolve",
            "format": "number"
        },
        {
            "key": "g_per_l",
            "label": "Fertiliser per litre",
            "format": "number"
        },
        {
            "key": "g_per_us_gal",
            "label": "Fertiliser per US gallon",
            "format": "number"
        },
        {
            "key": "elemental_pct",
            "label": "Elemental nutrient in the fertiliser",
            "format": "percent"
        },
        {
            "key": "stock_g_per_l",
            "label": "Fertiliser per litre of stock solution",
            "format": "number"
        }
    ],
    "formula": {
        "text": "Grams = ppm × Litres ÷ (Elemental% × 10);  Elemental% = Label% × Factor (P₂O₅ → P: 0.4364; K₂O → K: 0.8301)",
        "variables": {
            "ppm": "mg of the nutrient per litre of solution",
            "Factor": "mass share of the element in its oxide, from atomic weights",
            "Stock ratio": "how many times stronger the stock is than the final solution"
        }
    },
    "worked_example": {
        "inputs": {
            "target_ppm": "200",
            "content": "15.5",
            "label_form": "element",
            "volume": "100",
            "volume_unit": "l",
            "stock_ratio": "100"
        },
        "steps": [
            "Nitrogen needed = 200 mg/L × 100 L = 20,000 mg = 20 g.",
            "Fertiliser = 20 g ÷ 0.155 = 129.03 g.",
            "For a 100× stock: 1.2903 g/L × 100 = 129.03 g per litre of stock."
        ],
        "result": "To reach 200 ppm nitrogen in 100 L with a 15.5% N fertiliser, dissolve about 129 g."
    },
    "interpretation": "A fertiliser supplies several nutrients at once, so calculate the main one and then check what the others come to (ppm of the other nutrient = grams per litre × its % × 10). Confirm the final solution with an EC meter.",
    "assumptions": [
        "The fertiliser dissolves fully and the volume change from dissolving it is negligible."
    ],
    "limitations": [
        "Nutrients already in the source water are not subtracted.",
        "Compatibility of fertilisers in one stock tank (calcium with sulphates or phosphates) is not checked."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "Why convert P₂O₅ and K₂O?",
            "answer": "Labels in many countries give phosphate and potash as oxides, while recipes give elemental P and K. 1% P₂O₅ is 0.436% P and 1% K₂O is 0.830% K."
        },
        {
            "question": "What does a 100× stock mean?",
            "answer": "The stock is 100 times stronger than the final solution, so an injector set to 1:100 dilutes it to the target."
        }
    ],
    "sources": [],
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    ],
    "disclaimer": null,
    "publisher": "GM¹X CalcVerse"
}