{
    "name": "Construction Schedule Float Calculator",
    "url": "https://calculators.geekmidst.com/calculators/construction-schedule-float-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/construction-schedule-float-calculator.md",
    "category": "Construction",
    "description": "Calculate an activity’s total float and free float from its early start, duration, late finish and the earliest start of its successors.",
    "summary": "Total float is how long an activity can slip without delaying the project; free float is how long it can slip without delaying the next activity. Both come from the critical path dates.",
    "also_called": [
        "Total float calculator",
        "Free float 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": "es",
            "label": "Early start (ES)",
            "type": "number",
            "default": "10",
            "unit": "day"
        },
        {
            "name": "duration",
            "label": "Duration",
            "type": "number",
            "default": "5",
            "unit": "days"
        },
        {
            "name": "lf",
            "label": "Late finish (LF)",
            "type": "number",
            "default": "20",
            "unit": "day"
        },
        {
            "name": "succ_es",
            "label": "Earliest early start of successors",
            "type": "number",
            "default": "17",
            "unit": "day"
        }
    ],
    "outputs": [
        {
            "key": "total_float",
            "label": "Total float",
            "format": "number"
        },
        {
            "key": "free_float",
            "label": "Free float",
            "format": "number"
        },
        {
            "key": "ef",
            "label": "Early finish (EF)",
            "format": "number"
        },
        {
            "key": "ls",
            "label": "Late start (LS)",
            "format": "number"
        },
        {
            "key": "status",
            "label": "Status",
            "format": "text"
        }
    ],
    "formula": {
        "text": "EF = ES + Duration;  LS = LF − Duration;  Total float = LF − EF = LS − ES;  Free float = ES(successor) − EF",
        "variables": {
            "ES, EF": "early start and finish from the forward pass",
            "LS, LF": "late start and finish from the backward pass"
        }
    },
    "worked_example": {
        "inputs": {
            "es": "10",
            "duration": "5",
            "lf": "20",
            "succ_es": "17"
        },
        "steps": [
            "EF = 10 + 5 = 15; LS = 20 − 5 = 15.",
            "Total float = 20 − 15 = 5 days.",
            "Free float = 17 − 15 = 2 days."
        ],
        "result": "The activity can slip 2 days without affecting its successor and 5 days without delaying the project."
    },
    "interpretation": "Activities with zero total float are on the critical path. Negative float means the schedule already misses a required date and needs recovery.",
    "assumptions": [
        "Finish-to-start links with no lag.",
        "Day numbers use the convention that an activity starting at ES finishes at ES + duration."
    ],
    "limitations": [
        "Covers one activity; it does not compute the network’s forward and backward passes."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "Who owns the float?",
            "answer": "It depends on the contract. Many contracts say float belongs to the project, which affects delay claims."
        },
        {
            "question": "Can free float exceed total float?",
            "answer": "No. Free float is always less than or equal to total float."
        }
    ],
    "sources": [],
    "related": [
        {
            "name": "Concrete Curing Time Plan Calculator",
            "url": "https://calculators.geekmidst.com/calculators/concrete-curing-time-plan-calculator"
        },
        {
            "name": "Labour Productivity Calculator",
            "url": "https://calculators.geekmidst.com/calculators/labor-productivity-calculator"
        },
        {
            "name": "Date Difference Calculator",
            "url": "https://calculators.geekmidst.com/calculators/date-difference-calculator"
        }
    ],
    "disclaimer": "Quantities are estimates. Confirm requirements with your engineer or supplier before ordering materials.",
    "publisher": "GM¹X CalcVerse"
}