Solar Inverter Size Chart

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The inverter is one of the most important components of a home or portable solar power system. Solar panels produce DC electricity, but you need an inverter to convert DC power into 120/220 volt AC electricity, Only after conversion can home appliances and other devices use it.

If you have a 1000 watt solar array, your inverter must be at least 1200 watts. There must be at least 10% reserve power available, 20% is even better for large off grid solar systems

Inverter Size Chart

The right way to size an inverter is to check the wattage. The inverter wattage must be the same or greater than your solar panel’s watts. Here is a chart that shows the watts consumption of various appliances and what inverter size you will need.

Note that this guide includes a 20% safety margin for the inverter watts. This safety percentage can be adjusted. A larger value is always advisable as it is better to have some extra power in reserve. If you can afford a higher margin, go for it. If you load 2500 watts , get a 3000 watt inverter. We recommend the PowerDrive PD3000 as it is built specifically for heavy loads.

These recommendations are based on typical watt consumption of these devices. Check your specific device for more accurate information.

Inverter Size (25-100W)

Appliance / DeviceMinimum Inverter Capacity
Mobile phone25-50W
CD player40W
Satellite dish75W

Inverter Size (100-175W)

Appliance / DeviceMinimum Inverter Capacity
Light bulb100
Mini fridge100 (up to 500 watts for surge)
Music player120
25 inch TV175

Inverter Size (400-1000W)

Appliance / DeviceMinimum Inverter Capacity
Gaming console600
1/2 inch drill700
Vacuum cleaner750
Coffe maker800
Hair dryer1000
Space heater1000
Sub pump1000

Inverter Size (Greater Than 100W)

Appliance / DeviceMinimum Inverter Size in Watts
40 inch fan1100
Circular saw1250

Again, the power consumption given here is for general estimates only. TVs, laptops, microwaves etc. come in various shapes and sizes. To get more specific values, check the power requirements of each appliance and gadget that you want to use.

You should also adjust the calculation based on what appliances you will use. If you only need to charge your phone and a light bulb, that is only 150 watts combined. A 200 watt portable unit such as the NDDI Direct Power Inverter will be sufficient for that. if you are going to run an air conditioner or a refrigerator in your RV, a more powerful inverter and battery are required.

How to Calculate Inverter Size

You have to combine the watts for all the appliances you need and add 20% to the result. That is the minimum inverter size you need.

  1. Check the watt ratings of each appliance and add them. If the wattage rating isn’t indicated, use this formula: voltage (120) x amps = watts. Do this for appliances you need.
  2. Once you have the total, add 20% as a safety margin. If you expect power surges and / or sensitive equipment, increase the safety margin to 50% to 100%.
  3. If you have a 100 watt laptop and a 100 watt DVD player, consider getting a 300 w inverter. This might seem like overkill, but it will account for any sudden spikes when in use.

Motor powered appliances and devices need an additional surge. The power surge requirement for refrigerators, electric saws, drills etc is 2 to 3x the “regular” watts they use. So a 500 watt fridge needs 1500 watts for the initial power surge. Check the user guide for each appliance for specific details on power surge requirements.

Bottom line: the watt usage given in these charts are for initial estimates only. You can use this information to get an idea of the inverter size and how much it will cost. But you still need to get the actual wattage number in the appliances you will use.

Make sure you know how many appliances you will need, and how many you will use at the same time. You might for example, want to run your laptop at night, turn on the light and use a music player simultaneously. As mentioned above, you have to add the totals plus safety margin.

Inverter Size Frequently Asked Questions

What Will a 400 Watt Power Inverter Run?

A 400 watt inverter can run a laptop, charge a mobile phone, music player, light bub and a small TV. Most blenders run on 400 watts, but you won’t be able to run anything else with it. 150 to 200 watts is sufficient for light travelers and campers, but for extra power, getting a 400 watt inverter is an option particularly for RV trips.

What Will a 1000 Watt Power Inverter Run?

You can run several appliances, microwaves, blenders, gaming consoles, toasters, vacuum cleaners and more. It is not sufficient to run a good sized refrigerator however, as the typical 16 inch cubic feet unit requires at least 1500 watts. For a cooler and other appliances however, 1000 watts is more than enough even for a fully decked RV.

What Will a 3000 Watt Power Inverter Run?

3000 watt inverters are in the heavy duty category and meant for power users. With this you can run washing machines, a refrigerator, microwave, and other kitchen appliances. You can run large TVs, laptop and video game consoles too.

While powerful, these inverters need a matching solar panel, and it can be hard to find any portable solar panels that produce this kind of power. When you’re in the 1,000+ range, you have to use large solar panels. You can connect several portable panels to get extra power, but that takes up a lot of space on an RV. This in turn requires a more powerful inverter.

Is a Bigger Inverter Better?

The need for a safety margin already suggests that a bigger inverter is better. But just how big is too big? Some say a 10% or 20% safety margin is enough. Anything more than that and you run the risk of deteriorating performance. So what do you do?

Our view is that the safety margin can be from 20% to 100%. While doubling your solar panel wattage may seem too much, it is best to be sure. Many appliances have power surge requirements, and if your inverter is just equal to your solar panel’s size, those devices can’t run.

As for performance, well designed solar power systems should be able to offset that. There will always be some losses when the sun’s energy is converted to power, regardless of the solar panel or inverter you have. What is more important is you have sufficient watts to run the devices you need.

The need for extra power can be illustrated easily. Suppose you add all the watts of all the devices you use. You get an inverter that is the same size or just slightly larger. What if during your trip you suddenly needed to use more appliances? If the inverter is large enough, it can accommodate that extra need.

What is the Right Inverter Size Input Voltage?

For portable solar panels in the 100 watt range, 12V, 24V or 48V will be fine. If you have a more powerful inverter, higher voltage is required. This information will be provided in the inverter, and this will prove useful if you want to connect it direct to a solar panel.

What is Inverter Watt Rating?

As we mentioned, inverter size is measured in watts. There are two ways this measurement is carried out, continuous watts and surge watts. It is important that you consider this since many people make mistakes ,assuming running/continuous watts is peak/surge watts and vice versa.

Continuous Watts

This refers to the total number of watts an inverter can provided continuously. A 3000 watt inverter provides 3000 watts of continuous nonstop power. As long as your devices don’t exceed 300 watts, the inverter will have no problem running them at the same time. You can also save on power by buying solar powered appliances or camping appliances..

Surge Watts

Surge watts refers to the maximum peak power the inverter can provide for limited periods. Motorized appliances need surge power to start, and your inverter must be capable of providing this. If your devices require 400 watts and you have 300 continuous / 200 surge inverter, it is not enough .A 3000 watt inverter usually has 6000W surge power, or double the running watts.


Most of the attention in solar power is focused on solar panels, but do not neglect the inverter. Without it you won’t be able to convert the sun’s energy into usable electrical power for appliances. By making sure you have the right inverter, you won’t run into any trouble getting your appliances to run properly.