Whether you're powering a job site without utility hookup, providing backup power for an event, or keeping critical operations running during a grid outage, generator rentals are one of the most common and practical equipment rentals available.
This guide helps you choose the right generator size, understand the costs, and ask the right questions before you rent.
Understanding Generator Sizes
Generator output is measured in kilowatts (kW) — the higher the kW, the more equipment it can run simultaneously.
Small Portable Generators (1–10 kW)
- Best for: Small job sites, camping, food trucks, residential backup
- Powers: Lights, hand tools, small power tools, refrigerator
- Daily rental: $60–$150
- Example loads: A 5 kW generator can run a few lights, a refrigerator, and a small compressor
Mid-Size Generators (10–50 kW)
- Best for: Construction job sites, small events, commercial backup
- Powers: Multiple large tools, HVAC units, commercial kitchen equipment
- Daily rental: $150–$400
- Example loads: A 25 kW unit can run a construction site with multiple power tools, site lighting, and a job site trailer
Large Industrial Generators (50–500+ kW)
- Best for: Large events, data centers, hospitals, industrial facilities, large construction projects
- Powers: Entire buildings, large HVAC systems, industrial machinery
- Daily rental: $400–$2,500+
- Example loads: A 100 kW generator can power a small commercial building or a large outdoor event
How to Calculate the Generator Size You Need
Follow these steps to estimate your power requirement:
Step 1: List every electrical item you'll run at the same time.
Step 2: Find the wattage of each item.
- Power tools typically list watts or amps on the nameplate (Watts = Amps × Volts)
- HVAC units and motors have higher "starting watts" (2–3× running watts)
Step 3: Add up running watts, then identify the item with the highest starting watts.
Step 4: Total = sum of all running watts + (largest starting watts − its running watts)
Step 5: Add a 20–25% safety margin.
Example:
- 10 lights × 100W each = 1,000W running
- 1 air compressor: 2,000W running, 6,000W starting
- Misc tools: 1,500W running
- Total running: 4,500W
- Surge allowance: 6,000 − 2,000 = 4,000W
- Peak demand: 8,500W
- With 25% buffer: ~10,600W → rent a 12 kW generator
Generator Rental Costs
| Generator Size | Daily Rate | Weekly Rate | Monthly Rate | |---------------|-----------|-------------|-------------| | 2–6 kW (portable) | $60–$100 | $200–$350 | $500–$900 | | 8–15 kW | $120–$200 | $350–$600 | $900–$1,800 | | 20–50 kW | $200–$450 | $600–$1,400 | $1,800–$4,500 | | 60–100 kW | $450–$800 | $1,400–$2,500 | $4,500–$9,000 | | 125–250 kW | $800–$1,500 | $2,500–$5,000 | $9,000–$18,000 | | 300–500 kW | $1,500–$2,500 | $5,000–$9,000 | $18,000–$35,000 |
Rates do not include fuel, delivery, or cable rental.
Fuel Types
Diesel
The most common for mid-size to large rentals. Diesel generators are efficient, durable, and widely available. Typical consumption: 0.5–1 gallon per hour per 10 kW at 50% load.
Propane (LP)
Cleaner burning than diesel. Good for indoor or semi-indoor events where exhaust is a concern. Fuel costs tend to be higher.
Natural Gas (NG)
Used for permanent or semi-permanent standby installations. Requires a gas line connection.
Gasoline
Common for small portable units. Easy to fuel but less efficient for extended operation than diesel.
Additional Rental Costs to Budget For
- Delivery and setup: $100–$500 depending on size and distance
- Fuel: Usually not included — budget carefully based on runtime and load
- Electrical cabling: Power distribution panels and cabling are often rented separately ($50–$300/day)
- Automatic Transfer Switch (ATS): Required if connecting to a building's electrical system ($200–$600/day)
- Load bank testing: Some rentals for critical applications include pre-rental load testing
What to Ask Before You Rent
- Is the generator load tested and inspected before delivery?
- Does the rate include a fuel load or is the tank empty on delivery?
- What's the 24-hour emergency contact number if the generator fails?
- Does the company provide a transfer switch or power distribution panel?
- What's the noise level (dB rating)? — Critical for residential areas and events with noise ordinances
- Is there a minimum rental period?
- Who handles refueling during a multi-day rental?
Generator Safety Tips
- Never operate a generator indoors or in enclosed spaces — carbon monoxide is odorless and deadly
- Keep generators at least 20 feet from any occupied structure
- Always use a ground fault circuit interrupter (GFCI) for outdoor electrical connections
- Don't overload the generator — use the calculated capacity, not the maximum rated output
- Keep a dry-powder or CO2 fire extinguisher nearby
- Check oil level daily for extended rentals
Find Generator Rentals Near You
Search our directory to find equipment rental companies in your area that carry generators. Many offer same-day or next-day delivery for emergency power needs.