Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Capacity utilization
84.7%
Total monthly capacity
14,175
Headroom (units)
2,175
Minimum shifts needed for this demand
2
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How to use this
- 1Enter units produced per hour (one line).
- 2Enter net productive hours per shift (hrs).
- 3Enter shifts per day.
- 4Enter production days per month.
- 5Enter required monthly volume (units).
- 6Read your capacity utilization on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
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.
Worked example
Using the values the calculator loads with:
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
Results
- Capacity utilization: 84.7%
- Total monthly capacity: 14,175
- Headroom (units): 2,175
- Minimum shifts needed for this demand: 2
What each field means
Inputs
- Units produced per hour (one line)
- The units produced per hour (one line) used in the calculation. Starts at 45 so you have a working example on load.
- Net productive hours per shift (hrs)
- The net productive hours per shift used in the calculation, measured in hrs. Starts at 7.5 hrs so you have a working example on load.
- Shifts per day
- The shifts per day used in the calculation. Starts at 2 so you have a working example on load. Accepted range: 1–4.
- Production days per month
- The production days per month used in the calculation. Starts at 21 so you have a working example on load. Accepted range: 1–31.
- Required monthly volume (units)
- The required monthly volume used in the calculation, measured in units. Starts at 12000 units so you have a working example on load.
Results
- Capacity utilization
- Returned as a percentage and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total monthly capacity
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Headroom (units)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Minimum shifts needed for this demand
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
What utilization level should I target?
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.
Is a third shift ever a bad idea even if it meets capacity math?
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.
How do I get an accurate units-per-hour figure?
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.
Should I plan capacity around peak demand or average demand?
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.
Accuracy and 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.
Related tools
Takt Time Calculator
The pace you must produce at to match customer demand — no faster, no slower.
Cycle Time vs. Demand Calculator
Find out if your process can keep up with orders, and how many stations you need.
OEE Calculator (Overall Equipment Effectiveness)
Availability × performance × quality — the real health of a machine or line.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Capacity vs. Shifts Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/capacity-vs-shifts
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/capacity-vs-shifts" target="_blank" rel="noopener">Capacity vs. Shifts Calculator — RevenueLab</a> (2026).</p>
Source: [Capacity vs. Shifts Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/capacity-vs-shifts) (2026).