Machine Energy Per Part Calculator
The electricity a machine consumes per part — the cutting or forming energy plus its share of the idle power drawn while waiting — with the cost per part, per shift and the waste that idling represents.
A machine draws power in two ways: the running power during a cycle, which is easy to see, and the idle power — hydraulics, controls, cooling — that runs whether or not a part is being made.
How the machine energy per part calculator works
A machine draws power in two ways: the running power during a cycle, which is easy to see, and the idle power — hydraulics, controls, cooling — that runs whether or not a part is being made. Per part, the idle power is spread over however many parts the machine actually makes, so a machine that waits for half the shift carries a large idle overhead into every part.
Cutting idle time, or switching to a standby mode, is usually worth more than a more efficient motor.
Formula: per part = P_run × t_cycle + P_idle × idle hours / parts; cost = energy × tariff
Worked examples
| Inputs | Energy per part (kWh) | Note |
|---|---|---|
| A 15 kW machine idle 30% of the shift | 0.20357 | idle is a fifth of the energy |
| Never idle | 0.1875 | running energy only |
| Mostly waiting | 0.275 | idle dominates |
FAQFrequently asked questions
Why allocate idle power to parts?
Because it is paid for and the parts are what is sold. A machine idle half the day puts half a day of idle power into every part it does make.
What is a typical idle power?
Fifteen to forty per cent of running power for machine tools — hydraulics, chillers, controls and lighting stay on. Presses and furnaces can be higher.
How do I cut it?
Standby modes that shut hydraulics and chillers after a few idle minutes, and scheduling that keeps the machine busy. Both are cheaper than a new drive.
Does this include compressed air?
Only if you put it in the running power. Compressed air is often the largest hidden energy cost on a shop floor and deserves its own line.
How does this relate to carbon?
Multiply the energy per part by your grid's intensity for embodied operational carbon per part — increasingly a number customers ask for.
Where these figures come from
- Nakajima (1988) — Introduction to TPM — the origin of Overall Equipment Effectiveness and its six big losses
- OSHA — the US workplace safety administration
Last checked: September 2026. Definitions follow standard operations-management practice; where plants commonly differ, the page says so.