The general sizes of generators you typically need for construction sizes are small (up to 5000 peak watts), medium (up to 12000 peak watts), and big (12000+ peak watts to much much more).
As you can expect, these are very rough estimations. Construction sites can vary immense amounts in power needs.
To get a somewhat better idea, you can look at the power need estimations of the construction site tools in the chart below and follow the steps after that.
However, you don’t want to take these numbers too seriously either.
Individual tool strengths and brands can still vary a lot in terms of the watts, amps, and volts they need.
In turn, the size of the construction site generator you need can definitely vary too.
To play it safe, you would want to figure out the exact power needs of your construction site(s) and choose a generator with that information.
Construction site wattage chart
To get a more precise idea of what size generator you need for your construction site you want to know what power consumption you can expect from your individual tools.
In the chart below, you can find some rough general guidelines for the wattage requirements you can expect according to websites like Honda, Lowes, Northern Tool, and Don Rowe.
| Construction Site Tool | Running Watts | Additional Starting Watts | Total Starting Watts |
|---|---|---|---|
| Air Compressor (1/2 HP) | 975 | 625 | 1600 |
| Air Compressor (1 HP) | 1400 | 3600 | 5000 |
| Airless Paint Sprayer | 600 | 1200 | 1800 |
| Angle Grinder | 900 | 900 | |
| Battery Charger (15 amp) | 500 | 200 | 700 |
| Band Saw | 1200 | 1200 | |
| Belt Sander (3″) | 1200 | 2400 | 3600 |
| Bench Grinder (8″) | 1400 | 1100 | 2500 |
| Circular Saw (7.25″) | 1400 | 2300 | 3700 |
| Coffee Maker | 600 | 600 | |
| Concrete Vibrator (1 HP) | 1080 | 1080 | |
| Concrete Vibrator (3 HP) | 2400 | 2400 | |
| Disc Sander | 1200 | 1200 | |
| Electric Drill (3/8″) | 440 | 160 | 600 |
| Electric Drill (1/2″) | 600 | 300 | 900 |
| Fan Duty (1/4 HP) | 650 | 550 | 1200 |
| Floodlight | 150 | 150 | |
| Halogen Lights | 90 | 90 | |
| Hammer Drill | 700 | 300 | 1000 |
| Heat Gun | 1500 | 1500 | |
| Impact Driver | 500 | 500 | |
| Impact Wrench | 700 | 700 | |
| Jack Hammer | 1260 | 1260 | |
| Jig Saw | 700 | 700 | |
| Laptop | 250 | 250 | |
| Miter Saw | 1800 | 3300 | 5100 |
| Multi Tool | 400 | 400 | |
| Orbital Sander | 500 | 500 | |
| Printer | 600 | 600 | |
| Quartz Halogen Work Light (1000 Watt) | 1000 | 1000 | |
| Radial Arm Saw | 1000 | 1000 | 2000 |
| Rebar Cutter | 2400 | 2400 | |
| Reciprocating Saw | 1200 | 800 | 2000 |
| Rotary Hammer (15 amp) | 1800 | 1800 | |
| Sump Pump (1/3 HP) | 800 | 500 | 1300 |
| Sump Pump (1/2 HP) | 1050 | 1100 | 2150 |
| Table Saw (10″) | 2000 | 2000 | 4000 |
| Wall Chaser | 2000 | 2000 | |
| Wood Router | 1650 | 1650 |
Keep in mind that individual brands and sizes often vary in power needs.
The numbers above are often leaning toward the stronger models since a construction site is more serious than a DIY session.
Additionally, this chart does not include amp or volt requirements (although portable generators often take care of these).
When in doubt, you want to check with your favorite brands or retailers about the power needs.
What size generator do you need for construction work?
You typically need at least a 5000 peak watt generator for construction work but often even bigger generators are necessary too.
With the wattage chart above, some extra research, and a few steps, you can find out what size generator you need for your construction work projects.
- Note down your construction site tools and find out the most watt-intensive combination that will run at the same time.
- Count up the running watts of these devices and add at least a 10% safety margin. Your generator will need at least this many continuous watts.
- Add the highest amount of additional starting watts and add at least a 10% safety margin to this number. Your generator will need at least this many peak watts.
In theory, you can replace step 3 with a thought process where you turn on your tools in the “optimal” way in terms of the biggest starting watts first.
This could potentially make it so you can work with a smaller generator.
That being said, the bigger your construction site, the harder it becomes to coordinate this optimal start sequence.
In turn, the extra power safety margin is likely not a bad idea.
What kind of generator do you need for a construction site?
You typically just need a non-inverter generator that can run on gasoline, diesel, or propane for your construction site.
However, inverter generators or other low THD generators may be necessary if you want to safely power electronics like a laptop, printer, and coffee machine.
On the flip side, many construction site tools can run on high THD power too.
This can save you some money since high THD portable generators tend to be more budget-friendly.
When it comes to portable generator fuel types, your main options are gasoline, dual fuel (propane too), and tri fuel (propane and natural gas too).
There are also bigger diesel generators if these align with your construction site needs and guidelines.
Your choice of fuel type for your construction site generator will depend on safety guidelines, your location, and your preferences.
- Related: Household Appliances Wattage Chart
