Some rough general categories for construction site generators 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, different construction sites will typically vary in exact power needs too.
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.
Keep in mind that individual brands and sizes often vary in power needs.
The numbers below 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.
|Construction Site Tool||Running Watts||Additional|
|Air Compressor (1/2 HP)||975||625||1600|
|Air Compressor (1 HP)||1400||3600||5000|
|Airless Paint Sprayer||600||1200||1800|
|Battery Charger (15 amp)||500||200||700|
|Belt Sander (3″)||1200||2400||3600|
|Bench Grinder (8″)||1400||1100||2500|
|Circular Saw (7.25″)||1400||2300||3700|
|Concrete Vibrator (1 HP)||1080||1080|
|Concrete Vibrator (3 HP)||2400||2400|
|Electric Drill (3/8″)||440||160||600|
|Electric Drill (1/2″)||600||300||900|
|Fan Duty (1/4 HP)||650||550||1200|
|Quartz Halogen Work Light|
|Radial Arm Saw||1000||1000||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|
What size generator do you need for construction work?
With the wattage chart below, 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?
Once you know more or less how many watts you need, you choose what kind of generator you need for your construction site.
Your main choices will be low THD/inverter generators vs non-inverter generators and what fuel types you want to use.
If you want to safely power electronics like a laptop, printer, and coffee machine, you generally want a low THD generator (or at least a separate inverter).
On the flip side, many construction site tools can 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.