{ "slug": "capacity-vs-shifts", "title": "Capacity vs. Shifts Calculator", "heading": "Production Capacity & Shift Planning Calculator", "category": "other", "url": "https://www.revenuelab.fyi/toolbox/capacity-vs-shifts", "summary": "How many shifts you need to hit a volume target, and the capacity headroom you'd have.", "description": "This calculator answers the practical staffing question behind a demand forecast: given how fast one machine or line runs, how many shifts (and how many machines) do you need to hit a required monthly or annual volume, and how much headroom does that leave for demand spikes or downtime. It multiplies units-per-hour capacity by net hours per shift and number of shifts to get total capacity, then compares that against your target volume to show utilization and whether you're understaffed, right-sized, or have room to spare. This is the calculation behind decisions like adding a second or third shift versus buying another machine — running more shifts on existing equipment is almost always cheaper than capital investment in a new machine, up to the point where a third shift's labor premium and reduced supervision quality make a new machine the better option.", "formula": "Total Capacity = Units per Hour × Net Hours per Shift × Shifts per Day × Days per Period. Utilization = Demand ÷ Total Capacity.", "dateModified": "2026-09-30", "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=capacity-vs-shifts", "inputs": [ { "id": "unitsPerHour", "label": "Units produced per hour (one line)", "kind": "number", "hint": null, "default": 45, "unit": null, "min": 0.1, "max": null }, { "id": "netHoursShift", "label": "Net productive hours per shift", "kind": "number", "hint": null, "default": 7.5, "unit": "hrs", "min": 0.5, "max": null }, { "id": "shiftsPerDay", "label": "Shifts per day", "kind": "number", "hint": null, "default": 2, "unit": null, "min": 1, "max": 4 }, { "id": "daysPerMonth", "label": "Production days per month", "kind": "number", "hint": null, "default": 21, "unit": null, "min": 1, "max": 31 }, { "id": "demandMonthly", "label": "Required monthly volume", "kind": "number", "hint": null, "default": 12000, "unit": "units", "min": 0, "max": null } ], "outputs": [ { "id": "utilization", "label": "Capacity utilization", "format": "percent", "hint": null, "primary": true }, { "id": "capacityMonthly", "label": "Total monthly capacity", "format": "number", "hint": null, "primary": false }, { "id": "headroomUnits", "label": "Headroom (units)", "format": "number", "hint": null, "primary": false }, { "id": "shiftsNeeded", "label": "Minimum shifts needed for this demand", "format": "number", "hint": null, "primary": false } ], "worked_example": { "inputs": [ "Units produced per hour (one line): 45", "Net productive hours per shift: 7.5 hrs", "Shifts per day: 2", "Production days per month: 21", "Required monthly volume: 12000 units" ], "outputs": [ "Capacity utilization: 84.7%", "Total monthly capacity: 14,175", "Headroom (units): 2,175", "Minimum shifts needed for this demand: 2" ] }, "how_to": { "title": "How to use this", "steps": [ "Enter units produced per hour (one line).", "Enter net productive hours per shift (hrs).", "Enter shifts per day.", "Enter production days per month.", "Enter required monthly volume (units).", "Read your capacity utilization 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": { "unitsPerHour": 27, "netHoursShift": 4.5, "shiftsPerDay": 1, "daysPerMonth": 13, "demandMonthly": 7200 } }, { "name": "Typical", "description": "Defaults — the most common real-world setup.", "values": { "unitsPerHour": 45, "netHoursShift": 7.5, "shiftsPerDay": 2, "daysPerMonth": 21, "demandMonthly": 12000 } }, { "name": "Ambitious", "description": "Higher-end numbers — what if things really pop?", "values": { "unitsPerHour": 72, "netHoursShift": 12, "shiftsPerDay": 3, "daysPerMonth": 31, "demandMonthly": 19200 } } ], "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": "What utilization level should I target?", "a": "Running consistently above 85-90% utilization leaves little room to absorb downtime, rush orders, or demand spikes without missing shipments. Most planners aim for 75-85% planned utilization to keep a buffer, adding overtime or a partial extra shift to handle the rest." }, { "q": "Is a third shift ever a bad idea even if it meets capacity math?", "a": "Yes — third (overnight) shifts typically see higher turnover, need a shift premium (often 8-15% more in wages), and get less supervisory support, often resulting in lower actual output-per-hour than the math assumes. Many shops find a second shift plus planned overtime more reliable than adding a third shift." }, { "q": "How do I get an accurate units-per-hour figure?", "a": "Pull it from actual production data (parts made ÷ hours run) over a representative recent period, not a theoretical machine spec. Real-world output is almost always lower than nameplate rated speed once changeovers, minor stops, and pace variation are included." }, { "q": "Should I plan capacity around peak demand or average demand?", "a": "Plan base staffing around average-to-typical demand and use overtime, temp labor, or outsourcing to cover peak periods. Sizing permanent shift structure to peak demand means paying for idle capacity most of the year." } ], "related": [ "https://www.revenuelab.fyi/toolbox/takt-time-calculator", "https://www.revenuelab.fyi/toolbox/cycle-time-vs-demand", "https://www.revenuelab.fyi/toolbox/oee-calculator" ], "license": "CC-BY-4.0", "citation": "RevenueLab — Capacity vs. Shifts Calculator (https://www.revenuelab.fyi/toolbox/capacity-vs-shifts)" }