Electricity is typically one of the top 3 operating costs for any industrial facility. Yet many plant managers don't have a clear formula to estimate or monitor it. This guide walks you through exactly how to calculate electricity cost for a factory, machine by machine or at the whole-plant level.
The core calculation is straightforward:
To use this formula you need three values:
Power consumption is usually listed on the equipment nameplate or in the manual. Common sources:
| Equipment | Typical Power (kW) |
|---|---|
| Industrial motor (10 HP) | ~7.5 kW |
| Industrial motor (50 HP) | ~37 kW |
| Air compressor (25 HP) | ~18.5 kW |
| CNC machine | 5–25 kW depending on model |
| Industrial furnace (small) | 50–200 kW |
| Injection moulding (150T) | ~22 kW |
If you only know the rating in HP (horsepower), convert it:
Example: A 20 HP motor = 20 × 0.746 = 14.9 kW
Note: The nameplate shows the maximum load. Real-world consumption is often 70–90% of nameplate depending on load factor. For accurate numbers, use a clamp meter or power analyzer.
How many hours does each machine run per month?
| Scenario | Hours/Month (approx.) |
|---|---|
| Single shift (8 hrs/day, 25 days) | 200 hours |
| Double shift (16 hrs/day, 25 days) | 400 hours |
| Triple shift / continuous | 600–720 hours |
Check your electricity bill for the energy charge per kWh. In India, industrial tariffs typically range from ₹5 to ₹9 per kWh depending on state and voltage level. In the US, industrial rates typically range from $0.06 to $0.12 per kWh.
Note: Your bill may also include fixed charges, demand charges, and power factor penalties — see below.
Let's walk through a complete example:
Many industrial electricity bills include a demand charge — a fee based on your peak power demand in kVA or kW, not just the total energy consumed. This can add 20–40% to your bill.
To reduce demand charges: avoid running all heavy machinery simultaneously, stagger startup times, and use load scheduling systems.
Poor power factor (below 0.9 or 0.95) means your plant is drawing reactive power from the grid. Many utilities charge a penalty for this. Improving power factor using capacitor banks reduces your bill and can improve equipment efficiency.
Use the CalcNetra Power Factor Calculator to find the right capacitor size for your plant.
If your factory has multiple machines and you want to estimate total monthly energy, CalcNetra's Monthly Energy Calculator lets you enter multiple loads at once and get a combined estimate.
How do I calculate kWh consumption of a machine?
Multiply the machine's power in kW by the number of hours it runs. For example, a 10 kW machine running for 8 hours consumes 10 × 8 = 80 kWh.
What is a typical electricity cost per unit for industry in India?
Industrial electricity tariffs in India typically range from ₹5 to ₹9 per kWh depending on the state, the voltage level (HT or LT), and the time of use. Check your DISCOM's latest tariff order for accurate rates.
Why is my actual electricity bill higher than my calculation?
Several factors can increase the bill beyond basic energy consumption: fixed monthly charges, demand charges based on peak kVA, power factor penalty, fuel surcharge adjustments, and taxes/levies. Always review your bill structure carefully.
How much does electricity cost per hour for a factory?
It depends on your plant size. A small factory (50 kW average load, ₹7/kWh) would cost 50 × 7 = ₹350 per hour. A large plant (500 kW) at the same rate would cost ₹3,500 per hour.
Can I reduce electricity bills by shifting to off-peak hours?
Yes — if your utility offers time-of-use (TOU) tariffs with lower rates at night or weekends, scheduling energy-intensive processes during off-peak hours can meaningfully reduce your bill.
Calculate your factory's electricity cost right now — free, no login required:
Open Electricity Cost Calculator →Related: Power Factor Calculator | Monthly Energy Calculator | OEE Calculator