{
  "slug": "deadline-calculator",
  "title": "Deadline Calculator",
  "heading": "Project Deadline Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/deadline-calculator",
  "summary": "Back into a start date from a due date and effort estimate.",
  "description": "Work backwards from the deadline: divide total effort by daily capacity, add buffer, and you get the latest possible start date that still lands on time.",
  "formula": "Start = Due date − (effort hours ÷ daily capacity × buffer) working days.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=deadline-calculator",
  "inputs": [
    {
      "id": "due",
      "label": "Due date",
      "kind": "date",
      "hint": null,
      "default": null
    },
    {
      "id": "effort",
      "label": "Total effort",
      "kind": "number",
      "hint": null,
      "default": 60,
      "unit": "hours",
      "min": 1,
      "max": null
    },
    {
      "id": "capacity",
      "label": "Hours available per working day",
      "kind": "number",
      "hint": null,
      "default": 5,
      "unit": null,
      "min": 0.5,
      "max": 24
    },
    {
      "id": "buffer",
      "label": "Buffer",
      "kind": "number",
      "hint": null,
      "default": 25,
      "unit": "%",
      "min": 0,
      "max": 100
    }
  ],
  "outputs": [
    {
      "id": "start",
      "label": "Latest safe start date",
      "format": "raw",
      "hint": null,
      "primary": true
    },
    {
      "id": "workDays",
      "label": "Working days required",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "calendarDays",
      "label": "Calendar days required",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "totalHours",
      "label": "Total hours with buffer",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "bufferHours",
      "label": "Buffer hours",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "weeks",
      "label": "Working weeks",
      "format": "decimal",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Due date: 2026-09-30",
      "Total effort: 60 hours",
      "Hours available per working day: 5",
      "Buffer: 25 %"
    ],
    "outputs": [
      "Latest safe start date: Wednesday, September 9, 2026",
      "Working days required: 15",
      "Calendar days required: 21",
      "Total hours with buffer: 75",
      "Buffer hours: 15",
      "Working weeks: 3"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter due date.",
      "Enter total effort (hours).",
      "Enter hours available per working day.",
      "Enter buffer (%).",
      "Read your latest safe start date 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": {
        "due": "2026-09-30",
        "effort": 36,
        "capacity": 3,
        "buffer": 15
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "due": "2026-09-30",
        "effort": 60,
        "capacity": 5,
        "buffer": 25
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "due": "2026-09-30",
        "effort": 96,
        "capacity": 8,
        "buffer": 40
      }
    }
  ],
  "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 project deadline calculator work?",
      "a": "Work backwards from the deadline: divide total effort by daily capacity, add buffer, and you get the latest possible start date that still lands on time. The underlying maths is: Start = Due date − (effort hours ÷ daily capacity × buffer) working days."
    },
    {
      "q": "What do I need to enter?",
      "a": "4 values: due date, total effort, hours available per working day, and buffer. 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 latest safe start date result mean?",
      "a": "It is returned as a plain value 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/business-days",
    "https://www.revenuelab.fyi/toolbox/add-days-to-date"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Deadline Calculator (https://www.revenuelab.fyi/toolbox/deadline-calculator)"
}