{
  "id": "tongue-weight",
  "version": "0efd44faa70e",
  "status": "published",
  "name": "Tongue Weight Calculator",
  "question": "What should my tongue weight be?",
  "summary": "Computes the tongue weight range for a trailer, 10 to 15% of the loaded trailer weight by default or the range in your manual, and the percentage a measured tongue weight is.",
  "category": "everyday-life",
  "subcategory": "travel-and-fuel",
  "url": "https://www.acalculator.org/everyday-life/tongue-weight-calculator",
  "markdown": "https://www.acalculator.org/everyday-life/tongue-weight-calculator.md",
  "kind": "function",
  "method": "tongue weight range = loaded trailer weight × lowest share ÷ 100 to loaded trailer weight × highest share ÷ 100; measured share = tongue weight ÷ loaded trailer weight × 100.",
  "assumptions": [
    "The trailer is a conventional (bumper-pull) trailer on a ball hitch; fifth-wheel and gooseneck trailers carry a larger share.",
    "The default range is 10% to 15%, the common US guidance for a conventional trailer (Hyundai’s manual); too little tongue weight makes a trailer sway. Kia’s US manual caps it at 10% and NSW Government gives about 5 to 10%. Set the range and the maximum tongue load your own manual gives."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "gtw": {
        "title": "Loaded trailer weight",
        "description": "The gross trailer weight: the trailer and everything loaded on it.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "mass",
        "minimum": 1,
        "maximum": 100000
      },
      "lo": {
        "title": "Lowest share",
        "description": "The lowest tongue weight your manual gives, as a percent of the loaded trailer weight.",
        "type": "number",
        "x-unit": "percent",
        "exclusiveMinimum": 0,
        "maximum": 100
      },
      "hi": {
        "title": "Highest share",
        "description": "The highest tongue weight your manual gives, as a percent of the loaded trailer weight.",
        "type": "number",
        "x-unit": "percent",
        "exclusiveMinimum": 0,
        "maximum": 100
      },
      "tw": {
        "title": "Measured tongue weight",
        "description": "Your tongue weight from a scale, to see its share of the trailer weight. Leave empty to skip.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "mass",
        "minimum": 1,
        "maximum": 100000
      }
    }
  },
  "outputs": {
    "minLb": {
      "label": "Lowest tongue weight, lb",
      "description": "Loaded trailer weight × lowest share, in pounds.",
      "format": "number"
    },
    "maxLb": {
      "label": "Highest tongue weight, lb",
      "description": "Loaded trailer weight × highest share, in pounds.",
      "format": "number"
    },
    "minKg": {
      "label": "Lowest tongue weight, kg",
      "description": "Loaded trailer weight × lowest share, in kilograms.",
      "format": "number"
    },
    "maxKg": {
      "label": "Highest tongue weight, kg",
      "description": "Loaded trailer weight × highest share, in kilograms.",
      "format": "number"
    },
    "share": {
      "label": "Measured share",
      "description": "Measured tongue weight ÷ loaded trailer weight × 100, in percent.",
      "format": "number"
    },
    "verdict": {
      "label": "Measured tongue weight is",
      "description": "Below, within or above the range.",
      "format": "text"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "gtw": 2267.96185,
      "lo": 10,
      "hi": 15
    },
    "outputs": {
      "minLb": 500,
      "maxLb": 750,
      "minKg": 226.796185,
      "maxKg": 340.1942775
    },
    "text": "Aim for a tongue weight of 500 to 750 lb."
  },
  "examples": [
    {
      "given": {
        "gtw": 2267.96185,
        "lo": 10,
        "hi": 15
      },
      "expect": {
        "minLb": 500,
        "maxLb": 750,
        "minKg": 226.796185,
        "maxKg": 340.1942775
      },
      "source": "hand calculation in content.mdx: 5,000 × 10% = 500 lb, 5,000 × 15% = 750 lb; 1 lb = 0.45359237 kg (NIST SP 811); Hyundai owner’s manual, If You Decide to Pull a Trailer: the tongue load measured at the hitch when fully loaded should be within 10–15% of the total weight of the trailer, https://ownersmanual.hyundai.com/full_webhelp/LX3/2026/en_US/topic_snf_hxj_x5b.html (retrieved 2026-10-18)"
    },
    {
      "given": {
        "gtw": 1587.5732950000001,
        "lo": 10,
        "hi": 15,
        "tw": 136.077711
      },
      "expect": {
        "minLb": 350,
        "maxLb": 525,
        "share": 8.571428571428571,
        "verdict": "below the range"
      },
      "source": "hand calculation in content.mdx: 300 ÷ 3,500 = 8.57%, under 10%; Hyundai owner’s manual, If You Decide to Pull a Trailer: the tongue load measured at the hitch when fully loaded should be within 10–15% of the total weight of the trailer, https://ownersmanual.hyundai.com/full_webhelp/LX3/2026/en_US/topic_snf_hxj_x5b.html (retrieved 2026-10-18)"
    },
    {
      "given": {
        "gtw": 2000,
        "lo": 10,
        "hi": 15,
        "tw": 250
      },
      "expect": {
        "minKg": 200,
        "maxKg": 300,
        "share": 12.5,
        "verdict": "within the range"
      },
      "source": "hand calculation in content.mdx: 250 ÷ 2,000 = 12.5%, within 10 to 15%; over the 10% that Kia’s US manual allows and NSW Government’s 5 to 10%; Hyundai owner’s manual, If You Decide to Pull a Trailer: the tongue load measured at the hitch when fully loaded should be within 10–15% of the total weight of the trailer, https://ownersmanual.hyundai.com/full_webhelp/LX3/2026/en_US/topic_snf_hxj_x5b.html (retrieved 2026-10-18); Kia owner’s manual (KA4, 2024, US), If you do decide to pull a trailer: tongue weight at most 10% of the loaded trailer weight, https://ownersmanual.kia.com/full_webhelp/KA4/2024/en_US/topics/t00397.html (retrieved 2026-10-18); NSW Government, Towing a trailer or caravan: as a general rule, the vehicle should carry about 5 to 10% of the loaded trailer’s mass at the coupling, https://www.nsw.gov.au/driving-boating-and-transport/roads-safety-and-rules/vehicle-safety-and-compliance/towing-a-caravan (retrieved 2026-10-18)"
    }
  ],
  "sources": [
    "Hyundai owner’s manual, If You Decide to Pull a Trailer: the tongue load measured at the hitch when fully loaded should be within 10–15% of the total weight of the trailer; never exceed the GVWR. https://ownersmanual.hyundai.com/full_webhelp/LX3/2026/en_US/topic_snf_hxj_x5b.html (retrieved 2026-10-18)",
    "Kia owner’s manual (KA4, 2024, US), If you do decide to pull a trailer: tongue weight at most 10% of the loaded trailer weight, and within the vehicle’s maximum tongue load. https://ownersmanual.kia.com/full_webhelp/KA4/2024/en_US/topics/t00397.html (retrieved 2026-10-18)",
    "NSW Government, Towing a trailer or caravan: as a general rule, the vehicle should carry about 5 to 10% of the loaded trailer’s mass at the coupling. https://www.nsw.gov.au/driving-boating-and-transport/roads-safety-and-rules/vehicle-safety-and-compliance/towing-a-caravan (retrieved 2026-10-18)",
    "NIST SP 811 (2008), Appendix B: 1 lb = 0.45359237 kg exactly. https://www.nist.gov/pml/special-publication-811 (retrieved 2026-10-18)"
  ],
  "related": [
    "towing-capacity",
    "tire-pressure"
  ],
  "changelog": []
}