Diesel Generator Fuel Consumption Chart: Complete Guide with Calculator
How much diesel does a generator use per hour? This complete fuel consumption chart covers every standard kVA rating from 5 to 1500 kVA at 25%, 50%, 75%, and 100% load — plus a formula to calculate your exact running cost per hour.
Rishabh Power Solutions Engineering Team
2 min read
Quick Answer
A diesel generator consumes approximately 0.25–0.30 litres per kWh at 75% load. A typical 100 kVA generator uses about 15 litres/hour at 75% load, costing roughly ₹1,300–₹1,400/hour at current diesel prices.
Fuel Consumption Chart: 5 kVA to 1500 kVA
| Generator (kVA) | kW (PF 0.8) | 25% Load | 50% Load | 75% Load | 100% Load |
|---|---|---|---|---|---|
| 5 | 4 | 0.5 L/hr | 0.8 L/hr | 1.1 L/hr | 1.5 L/hr |
| 10 | 8 | 0.8 L/hr | 1.3 L/hr | 1.8 L/hr | 2.5 L/hr |
| 15 | 12 | 1.2 L/hr | 1.8 L/hr | 2.6 L/hr | 3.5 L/hr |
| 25 | 20 | 2.0 L/hr | 3.0 L/hr | 4.0 L/hr | 5.5 L/hr |
| 50 | 40 | 3.5 L/hr | 5.5 L/hr | 7.8 L/hr | 10.5 L/hr |
| 62.5 | 50 | 4.3 L/hr | 6.8 L/hr | 9.6 L/hr | 13.0 L/hr |
| 75 | 60 | 5.0 L/hr | 8.0 L/hr | 11.3 L/hr | 15.3 L/hr |
| 100 | 80 | 6.5 L/hr | 10.5 L/hr | 15.0 L/hr | 20.5 L/hr |
| 125 | 100 | 8.0 L/hr | 13.0 L/hr | 18.5 L/hr | 25.0 L/hr |
| 200 | 160 | 12.5 L/hr | 20.5 L/hr | 29.0 L/hr | 40.0 L/hr |
| 250 | 200 | 15.5 L/hr | 25.5 L/hr | 36.0 L/hr | 49.0 L/hr |
| 500 | 400 | 30.0 L/hr | 50.0 L/hr | 71.0 L/hr | 97.0 L/hr |
| 750 | 600 | 44.0 L/hr | 74.0 L/hr | 105.0 L/hr | 143.0 L/hr |
| 1000 | 800 | 58.0 L/hr | 97.0 L/hr | 138.0 L/hr | 189.0 L/hr |
| 1500 | 1200 | 86.0 L/hr | 143.0 L/hr | 204.0 L/hr | 279.0 L/hr |
How to Calculate Running Cost Per Hour
Running Cost (₹/hr) = Fuel Consumption (L/hr) × Diesel Price (₹/L)
Example: 100 kVA at 75% Load in Delhi
- Fuel: 15.0 L/hr × ₹87.67/L = ₹1,315/hour
- 8 hours/day = ₹10,520/day
- 25 days/month = ₹2,63,000/month
Why Load Factor Matters
Running at 25% load burns 0.325 L per kWh — 30% more per unit than 75% load. If your generator consistently runs below 40% load, it's oversized. Consider downsizing to save 15–25% on fuel.
7 Factors That Affect Fuel Consumption
- Load level — optimal at 75%
- Engine condition — worn injectors increase consumption 10–20%
- Altitude — above 1,000m, engines lose ~3.5% power per 300m
- Temperature — above 40°C, expect 2–5% more consumption
- Fuel quality — use BS-VI grade diesel
- Maintenance — regular service saves 5–15%
- Load type — reactive loads with low power factor increase demand
Frequently Asked Questions
How much diesel does a 62.5 kVA generator consume per hour?
Approximately 9.6 L/hr at 75% load. At Delhi diesel prices (₹87.67/L), that's about ₹841 per hour.
How many litres per hour does a 500 kVA generator use?
About 71 L/hr at 75% load. Monthly cost running 8 hours/day: approximately ₹12.4 lakh.
Is it bad to run a generator at low load?
Yes. Running below 30% load causes "wet stacking" — unburned fuel builds up, causing carbon deposits and engine damage.
Need Help?
Use our free kVA Calculator or request a quote. Call +91 9810145225.
Sources
- Hardy Diesel / FW Power / Generator Source fuel consumption charts
- Goodreturns / BusinessToday, Indian diesel prices (April 2026)
- Shakti Foundation, "Diesel Generators: Improving Efficiency in India"
Rishabh Power Solutions Engineering Team
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