{
  "slug": "jam-preserves-batch-cost",
  "title": "Jam & Preserves Batch Cost Calculator",
  "heading": "Cottage Jam & Preserves Batch Cost Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/jam-preserves-batch-cost",
  "summary": "Cost per jar for small-batch jam, jelly, or preserves accounting for cook-down loss.",
  "description": "Jam and preserves lose significant volume during cooking as water evaporates to reach setting point, typically 20-35% depending on fruit water content and how long the batch reduces. A recipe that starts with 10 cups of fruit and sugar doesn't yield 10 cups of finished jam, and producers who price off starting ingredient volume rather than finished jar count understate their real cost per jar. This calculator takes starting ingredient cost and volume, applies your expected cook-down loss percentage, and computes jars produced and cost per jar including jar and lid packaging cost, which matters for cottage food producers since packaging can be 15-25% of total cost per jar for small 8oz jars.",
  "formula": "Finished volume = starting volume × (1 − cook-down loss%). Jars = finished volume ÷ jar size. Cost/jar = (ingredient cost + packaging×jars + labor) ÷ jars.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=jam-preserves-batch-cost",
  "inputs": [
    {
      "id": "startVolumeCups",
      "label": "Starting fruit + sugar volume",
      "kind": "number",
      "hint": null,
      "default": 12,
      "unit": "cups",
      "min": 1,
      "max": null
    },
    {
      "id": "cookdownLossPct",
      "label": "Cook-down volume loss",
      "kind": "number",
      "hint": null,
      "default": 28,
      "unit": "%",
      "min": 5,
      "max": 50
    },
    {
      "id": "ingredientCost",
      "label": "Total ingredient cost for batch",
      "kind": "number",
      "hint": null,
      "default": 18,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "jarSizeOz",
      "label": "Jar size",
      "kind": "select",
      "hint": null,
      "default": "8",
      "options": [
        {
          "value": "4",
          "label": "4oz jar"
        },
        {
          "value": "8",
          "label": "8oz jar"
        },
        {
          "value": "16",
          "label": "16oz jar"
        }
      ]
    },
    {
      "id": "jarPackagingCost",
      "label": "Jar, lid, label cost per jar",
      "kind": "number",
      "hint": null,
      "default": 0.75,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "laborCost",
      "label": "Total labor cost for batch",
      "kind": "number",
      "hint": null,
      "default": 25,
      "unit": "$",
      "min": 0,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "costPerJar",
      "label": "Cost per jar",
      "format": "currency",
      "hint": null,
      "primary": true
    },
    {
      "id": "jars",
      "label": "Jars produced",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "totalCost",
      "label": "Total batch cost",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "finishedCups",
      "label": "Finished jam volume (cups)",
      "format": "decimal",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Starting fruit + sugar volume: 12 cups",
      "Cook-down volume loss: 28 %",
      "Total ingredient cost for batch: 18 $",
      "Jar size: 8oz jar",
      "Jar, lid, label cost per jar: 0.75 $",
      "Total labor cost for batch: 25 $"
    ],
    "outputs": [
      "Cost per jar: $5.73",
      "Jars produced: 8.6",
      "Total batch cost: $49.48",
      "Finished jam volume (cups): 8.6"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter starting fruit + sugar volume (cups).",
      "Enter cook-down volume loss (%).",
      "Enter total ingredient cost for batch ($).",
      "Enter jar size.",
      "Enter jar, lid, label cost per jar ($).",
      "Enter total labor cost for batch ($).",
      "Read your cost per jar 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": {
        "startVolumeCups": 7,
        "cookdownLossPct": 17,
        "ingredientCost": 11,
        "jarSizeOz": "8",
        "jarPackagingCost": 0.44999999999999996,
        "laborCost": 15
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "startVolumeCups": 12,
        "cookdownLossPct": 28,
        "ingredientCost": 18,
        "jarSizeOz": "8",
        "jarPackagingCost": 0.75,
        "laborCost": 25
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "startVolumeCups": 19,
        "cookdownLossPct": 45,
        "ingredientCost": 29,
        "jarSizeOz": "8",
        "jarPackagingCost": 1.2000000000000002,
        "laborCost": 40
      }
    }
  ],
  "limitations": [
    "Results are estimates before tax, fees, and inflation unless an input explicitly covers them.",
    "Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.",
    "This is educational maths, not financial advice. Check anything contractual with the lender or your accountant."
  ],
  "faq": [
    {
      "q": "Why does jam lose so much volume during cooking?",
      "a": "Reaching the gel/setting point for jam requires boiling off water until sugar concentration hits roughly 65-68 brix, and high-water-content fruits like strawberries and peaches can lose 30% or more of starting volume as steam during that reduction, while lower-water fruits like fig lose somewhat less."
    },
    {
      "q": "What's a realistic packaging cost share for small jars?",
      "a": "For an 8oz jar, glass jar plus two-piece lid plus a printed label commonly runs $0.60-1.00 depending on where you source jars and whether labels are custom printed or hand-stamped. On a jam that costs $2.50 total per jar, that's 25-40% of total cost, which is why small-batch producers scaling to 16oz jars often see meaningfully better margin per ounce sold."
    },
    {
      "q": "Should I count processing/canning time as separate from cooking time?",
      "a": "Yes, water-bath processing (typically 10-15 minutes plus cooling) adds real labor time beyond the stovetop cook, and if you're licensed under a cottage food law requiring specific processing steps for shelf stability, that time should be folded into your labor cost input rather than ignored as 'just waiting.'"
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/cottage-food-pricing",
    "https://www.revenuelab.fyi/toolbox/farmers-market-booth-breakeven"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Jam & Preserves Batch Cost Calculator (https://www.revenuelab.fyi/toolbox/jam-preserves-batch-cost)"
}