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Capacity planning and machine load

I have these orders to ship this month: do they fit? Paste the order book and the machines to see each resource’s load, the bottleneck and how much overtime, shifts, machines or outsourced hours you need, with the cost of each option.

Pre-sizing and estimating tool: results do not replace design, calculations or reports signed by a licensed professional, nor verification against the applicable codes and standards.

Pre-sizingRevised 11/02/2026
Period and calendar
Resources (machines and stations)
See what was read
Order book for the period
See what was read

An order that goes through several machines takes one line per machine, with the resource name spelled as in the resource list.

How to cover a capacity shortfall

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—Load of the most loaded resource
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Load vs. capacity by resource

Hours required as a % of hours available in the period; the line marks 100%.

Tap the chart to see the values.

Machine load by resource

How to cover the missing hours

For each resource above 100%: what each option requires, whether it fits the limits entered and what it costs in the period.

Where the load comes from

Hours required by each order at each resource, with the hours available.

Tap the chart to see the values.

Next step

Take this page’s results to another calculator with the fields already filled in.

The calculation report gathers this page's inputs, results, equations, assumptions and references, with fields for project, engineer and revision. The full report also includes the charts and interpretations, in color. In the print dialog, choose Save as PDF.

Method, assumptions and references

Equations used

Hours available = machines × days × shifts × (shift hours − breaks)
Hours required = Σ [quantity ÷ (1 − scrap) × standard time ÷ 60 ÷ efficiency + setup × batches ÷ 60]
Load = required ÷ available; shortfall = required − available; machines needed = required ÷ hours per machine
Overtime per machine per day = shortfall ÷ (machines × days); cost = shortfall × hour rate × (1 + premium × labor share)
Outsource = shortfall × hour rate × relative price; extra shift = shortfall × hour rate

Assumptions and limits

  • Infinite capacity over the period: it checks whether the load fits, without sequencing in time. Identical machines per resource, with the same efficiency and scrap for every product.
  • Setups are not affected by efficiency; overtime and extra days use the hour rate with the premium on the labor share only; the extra shift uses the normal hour rate and excludes night premium, hiring and training.
  • The calculator does not check legal working-time limits: labor law and union agreements are the user’s responsibility. The suggested option is the cheapest within the limits entered, not necessarily the best for the business.

Standards and technical documents

  • APICS / ASCM Dictionary, 16th ed., 2019 (capacity requirements planning, rated capacity = available time × utilization × efficiency)
  • Vollmann, T. E.; Berry, W. L.; Whybark, D. C.; Jacobs, F. R. Manufacturing Planning and Control for Supply Chain Management, 6th ed., McGraw-Hill, 2011
  • Slack, N.; Brandon-Jones, A.; Burgess, N. Operations Management, 10th ed., Pearson, 2022 (capacity planning and control)
  • Corrêa, H. L.; Gianesi, I. G. N.; Caon, M. Planejamento, Programação e Controle da Produção: MRP II/ERP, 6ª ed., Atlas, 2018
  • Nakajima, S. Introduction to TPM: Total Productive Maintenance, Productivity Press, 1988 (OEE)

U.S. regulations

  • Fair Labor Standards Act (29 U.S.C. 207): overtime at 1.5 times the regular rate above 40 hours per week for non-exempt employees
  • OSHA 29 CFR 1910.212: machine guarding when machines or shifts are added

Frequently asked questions

What is capacity requirements planning (CRP)?

It compares the hours the order book requires at each machine with the hours each machine has in the period. It shows the bottleneck, how much is missing and the cheapest way to cover it: overtime, Saturdays, an extra shift, a machine or outsourcing.

How does the calculator get the hours required?

For each order line: quantity ÷ (1 − scrap) × standard time ÷ efficiency, plus setup × number of batches. In the example the Machining center needs 364.6 h and has 315 h in the month (21 days × 2 shifts × 7.5 h), a 116% load.

Where do I get standard time, efficiency and scrap?

Standard time: routing or time study, in minutes per part, without losses. Efficiency: the machine’s measured OEE, or parts made ÷ parts possible at standard time. Scrap: the rate quality records. Without data, 75% efficiency and 2% scrap are a conservative starting point for machining.

How do I read the example?

The Machining center is short 49.6 h. Overtime alone would take 2.36 h a day, above the 2-hour limit; four Saturdays would cover it. The cheapest option within the limits is shown with a check mark in the options table; the CNC lathe, at 80%, is still green but close to the warning limit.

What is the ideal machine load?

There is no 100% in practice: breakdowns, shortages, rework and rush orders eat part of the time. Planning up to 80% to 85% of effective capacity usually keeps due dates. Above that, any surprise becomes a delay; below 50% there is idle capacity to sell.

Does the calculator decide when each order runs?

No. It checks whether the load fits in the period (infinite capacity, no time sequence). To decide the order and timing of each job at the bottleneck, use the job sequencing calculator, which receives the orders of the most loaded resource.

What are the limits?

It assumes the same efficiency for every product on a resource, identical machines, an operator whenever the machine runs and load spread over the period. It ignores due dates within the month, material shortages and queue time. Overtime cost applies the premium to labor only; check labor law and any union agreement before scheduling.