{
  "slug": "lawn-fertilizer",
  "title": "Lawn Fertilizer Calculator",
  "heading": "Lawn Fertilizer & Seed Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/lawn-fertilizer",
  "summary": "Bags of fertilizer and pounds of seed for your lawn size.",
  "description": "Fertilizer is applied by pounds of actual nitrogen per 1,000 square feet — usually one pound. The bag's first number is the nitrogen percentage, which is what turns a bag weight into an application rate.",
  "formula": "Bags = (Area ÷ 1,000 × lb N target) ÷ (bag weight × N%).",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=lawn-fertilizer",
  "inputs": [
    {
      "id": "area",
      "label": "Lawn area",
      "kind": "number",
      "hint": null,
      "default": 6000,
      "unit": "sq ft",
      "min": 100,
      "max": null
    },
    {
      "id": "nitrogen",
      "label": "Nitrogen in the bag (first number)",
      "kind": "number",
      "hint": null,
      "default": 24,
      "unit": "%",
      "min": 1,
      "max": 60
    },
    {
      "id": "bagWeight",
      "label": "Bag weight",
      "kind": "number",
      "hint": null,
      "default": 40,
      "unit": "lb",
      "min": 5,
      "max": 100
    },
    {
      "id": "targetN",
      "label": "Nitrogen target",
      "kind": "number",
      "hint": null,
      "default": 1,
      "unit": "lb per 1,000 sq ft",
      "min": 0.25,
      "max": 2
    },
    {
      "id": "seedRate",
      "label": "Seed rate",
      "kind": "number",
      "hint": null,
      "default": 5,
      "unit": "lb per 1,000 sq ft",
      "min": 1,
      "max": 12
    },
    {
      "id": "bagCost",
      "label": "Cost per bag",
      "kind": "number",
      "hint": null,
      "default": 32,
      "unit": "$",
      "min": 0,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "bagsRounded",
      "label": "Bags to buy",
      "format": "number",
      "hint": null,
      "primary": true
    },
    {
      "id": "productLbs",
      "label": "Pounds of product to spread",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "seedLbs",
      "label": "Pounds of grass seed",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "cost",
      "label": "Fertilizer cost",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "nNeeded",
      "label": "Pounds of actual nitrogen needed",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "bags",
      "label": "Exact bags required",
      "format": "decimal",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Lawn area: 6000 sq ft",
      "Nitrogen in the bag (first number): 24 %",
      "Bag weight: 40 lb",
      "Nitrogen target: 1 lb per 1,000 sq ft",
      "Seed rate: 5 lb per 1,000 sq ft",
      "Cost per bag: 32 $"
    ],
    "outputs": [
      "Bags to buy: 1",
      "Pounds of product to spread: 25",
      "Pounds of grass seed: 30",
      "Fertilizer cost: $32.00",
      "Pounds of actual nitrogen needed: 6",
      "Exact bags required: 0.63"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter lawn area (sq ft).",
      "Enter nitrogen in the bag (first number) (%).",
      "Enter bag weight (lb).",
      "Enter nitrogen target (lb per 1,000 sq ft).",
      "Enter seed rate (lb per 1,000 sq ft).",
      "Enter cost per bag ($).",
      "Read your bags to buy on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "area": 3600,
        "nitrogen": 14,
        "bagWeight": 25,
        "targetN": 0.6,
        "seedRate": 3,
        "bagCost": 19
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "area": 6000,
        "nitrogen": 24,
        "bagWeight": 40,
        "targetN": 1,
        "seedRate": 5,
        "bagCost": 32
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "area": 9600,
        "nitrogen": 38,
        "bagWeight": 65,
        "targetN": 1.6,
        "seedRate": 8,
        "bagCost": 51
      }
    }
  ],
  "limitations": [
    "Estimates assume standard, average conditions — local rules, pricing, and materials vary.",
    "Results are rounded for readability; add a buffer before ordering, booking, or committing.",
    "Double-check anything with a real cost attached against a local quote."
  ],
  "faq": [
    {
      "q": "How does the lawn fertilizer & seed calculator work?",
      "a": "Fertilizer is applied by pounds of actual nitrogen per 1,000 square feet — usually one pound. The bag's first number is the nitrogen percentage, which is what turns a bag weight into an application rate. The underlying maths is: Bags = (Area ÷ 1,000 × lb N target) ÷ (bag weight × N%)."
    },
    {
      "q": "What do I need to enter?",
      "a": "6 values: lawn area, nitrogen in the bag (first number), bag weight, nitrogen target, seed rate, and cost per bag. Each field starts with a sensible default, so you can change one number at a time and watch the result move."
    },
    {
      "q": "What does the bags to buy result mean?",
      "a": "It is returned as a whole number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds."
    },
    {
      "q": "Is this calculator free, and do I need an account?",
      "a": "Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser."
    },
    {
      "q": "How accurate is the result?",
      "a": "It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary."
    },
    {
      "q": "Who is this tool for?",
      "a": "It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/pool-volume",
    "https://www.revenuelab.fyi/toolbox/mulch-calculator"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Lawn Fertilizer Calculator (https://www.revenuelab.fyi/toolbox/lawn-fertilizer)"
}