Add the speakers, lights, bounce house blowers and food machines you plan to plug in. The calculator adds up the running watts and amps, checks the start-up surge and shows the generator that runs it all under 80% of its load. Free, no sign-up.
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Pick a ready-made setup or add each item and how many. This generator wattage calculator gives you the total running watts and amps, the start-up surge, the generator that fits with room to spare, and how much power is left to plug in.
Prefer to work it out by hand? These are the same four steps the generator calculator runs for you.
List What You Plug In
Speakers, lights, blowers and machines. Find the running watts on each label or in the chart below.
Add the Running Watts
That is the steady load. On a 120 volt outlet, amps = watts divided by 120.
Add the Start-Up Surge
Motors like blowers, ice shavers and fridges pull 2 to 3 times their running watts for a few seconds when they start.
Stay Under 80%
Pick a generator whose running watts are at least 25% above your total, so it never works past 80% of its load.
Typical running and starting watts for the gear we see at parties and events. Your own gear may differ, so check the label: watts = volts x amps.
| Equipment | Running watts | Starting watts | Amps (120 V) |
|---|---|---|---|
| Inflatables and Rides | |||
| Bounce house blower, 1.5 HP | 1,100 | 3,000 | 9.2 |
| Blower, 2 HP (big slides, obstacle courses) | 1,800 | 4,500 | 15 |
| Water slide pump | 300 | 900 | 2.5 |
| Concessions and Food | |||
| Cotton candy machine | 1,250 | 1,600 | 10.4 |
| Popcorn machine, 8 oz | 1,450 | 1,450 | 12.1 |
| Snow cone machine (ice shaver) | 850 | 2,000 | 7.1 |
| Hot dog roller grill (30 hot dogs) | 1,950 | 1,950 | 16.3 |
| Slushie machine, 2 bowl | 1,000 | 3,000 | 8.3 |
| Coffee urn, 100 cup | 1,500 | 1,500 | 12.5 |
| Beverage fridge or cooler | 200 | 1,000 | 1.7 |
| Sound and DJ | |||
| Powered speaker, 12 or 15 in | 350 | 350 | 2.9 |
| Powered subwoofer, 18 in | 500 | 500 | 4.2 |
| DJ controller and laptop | 150 | 150 | 1.3 |
| Full DJ booth (2 players, mixer, booth monitors) | 550 | 550 | 4.6 |
| Line array speaker, powered (per box) | 300 | 300 | 2.5 |
| Amplifier rack, 4 channel | 2,000 | 2,000 | 16.7 |
| Lighting and Effects | |||
| LED par or uplight | 85 | 85 | 0.7 |
| Moving head light, DJ size | 220 | 220 | 1.8 |
| Fog machine | 1,200 | 1,200 | 10 |
| Low fog machine | 2,150 | 3,000 | 17.9 |
| String lights, LED (100 ft) | 60 | 60 | 0.5 |
| String lights, bulb (100 ft) | 600 | 600 | 5 |
| Screens and Extras | |||
| TV, 55 to 65 in | 200 | 200 | 1.7 |
| Projector, 5,000 lumen | 300 | 300 | 2.5 |
| Photo booth with printer | 450 | 450 | 3.8 |
| Misting fan | 400 | 1,000 | 3.3 |
| Electric patio heater | 1,500 | 1,500 | 12.5 |
| Portable AC, 10,000 BTU | 1,050 | 3,000 | 8.8 |
Add the running watts of everything that runs at the same time, then add the biggest single start-up surge. Or let the generator size calculator do it for you.
One bounce house blower runs on a Predator 3500. Two blowers, or a big slide, need the Predator 5000. A DJ with speakers and lights runs on the 3500, and food machines add up fast. These are the setups we power most.
A DJ or PA system with two speakers, LED uplights and a laptop draw far less than people think. The Predator 3500 runs them with clean power that will not hum through the speakers.
A bounce house blower runs all day and needs a steady supply, plus a little extra power the moment it starts. The Predator 5000 is built for that, and it can run more than one blower when the sizes allow.
Concession machines heat up and pull a lot of power. A popcorn machine, a cotton candy machine and our hot dog grill each need a real share of a generator, so we plan them on the Predator 5000 or the two-generator package.
Not sure what size you need? Send us the list of what you are plugging in, from speakers to a popcorn machine, and we size it with you. If the load is more than two of our generators can carry, we say so before the event.
Running watts: Predator 3500 = 3,000 W, Predator 5000 = 3,900 W, Predator 11,500 = 9,000 W, towable diesel = 20 to 56 kW. Prices are per event, up to 6 hours, gas included.
Sound, DJ, lights and projectors
Free delivery in Brooklyn with a $595 order
Inflatables, food machines and bigger loads
Free delivery in Brooklyn with a $595 order
Water slides, several inflatables, DJ and food together
Free delivery in Brooklyn with a $595 order
Festivals, stages and big tent events
Delivered and towed anywhere in NY, NJ, CT and PA
Renting a bounce house, sound or a snow cone machine from us? The generator goes out on the same truck, and we size it to exactly what we bring. See our block party packages, where the generator is already planned in.
Add up the running watts of everything that will run at the same time, then add the biggest single start-up surge (the extra power a motor pulls for a few seconds when it starts). Choose a generator whose running watts are at least 25% above your total so it works under 80% of its load. The calculator above does all three steps.
A DJ with two powered speakers, a subwoofer and a few uplights uses about 2,000 running watts, so a Predator 3500 (3,000 running watts) covers it. Each food machine adds 850 to 1,950 watts and each bounce house blower about 1,100 watts, so most parties with sound plus one or two machines need the Predator 5000 or 11,500. Enter your list in the calculator for the exact size.
A 1.5 HP bounce house blower runs at about 1,100 watts and needs about 3,000 watts for a few seconds to start, so the right generator for one bounce house is a Predator 3500. Two bounce houses, or one big slide or obstacle course with a 2 HP blower (about 4,500 starting watts), need the Predator 5000.
Running watts are the steady power a device uses while it is on. Starting watts are the short surge a motor needs to start, often 2 to 3 times its running watts. Speakers and LED lights have no surge; blowers, ice shavers, slushie machines, fridges and AC units do.
On a regular 120 volt outlet, amps = watts divided by 120. A 1,200 watt fog machine draws 10 amps. A standard 15 amp circuit carries about 1,800 watts and a 20 amp circuit about 2,400 watts, which is why big loads are spread over several circuits or a generator.
A generator working near its limit runs hot, uses more fuel and can trip its breaker when a motor kicks on. Keeping the total under 80% of its running watts leaves room for surges and keeps the power steady for sound and lights all day.
A Predator 3500 gives 3,000 running watts and 3,500 starting watts. That runs a DJ setup with speakers and lights, or one bounce house, or a popcorn machine with a small sound system. Add a second blower or a hot dog grill and you need the Predator 5000.
The list is built for party and event equipment, but the method is the same for a home: add the running watts of what you need and the biggest starting surge. Whole-house backup should be planned with a licensed electrician. We rent generators for parties and events across NY, NJ, CT and PA.
Yes. It is free, with no sign-up. The price shown is an estimate for our rental generators, gas included; send us your list and the address for an exact quote.
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