Best PC Power Supply Calculators

Building a new PC is a process that presents many challenges, but choosing an appropriate PSU (power supply unit) is often overlooked. Power supply calculators tell you exactly what you need to know to make the right choice when buying a PSU. Keep reading to find out which calculator you should use.

The reason why PSUs are often overlooked is that they aren’t very expensive and there is a large variety of them, so people approach this subject with an air of nonchalance. Many believe that getting a 500-600W unit will be sufficient and they don’t give it much more thought.

The issue here is more complex than that and choosing the right PSU for your computer should be considered as important as getting the right GPU and CPU. As with those, there are tiers that relate to different budgets, but quality and capability are what you should focus on.

In the old days (well, perhaps ten or fifteen years ago), the responsibility fell to the would-be PC builder to manually calculate how much power their new gaming rig would require. You would need to calculate the usage of the graphics card, processor, RAM, and fans. It was a tedious task.

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Enter Power Supply Calculators

Fortunately, some very smart people devised a great solution: a power supply calculato

. We can now simply enter the models of each component we plan to use in our computer to receive an exact figure of how much power it will require.

PC Components
Your PC components need power. Image credit: CNET

Some people have gone even further and added a suggestion for the exact model that will fit your build. However, this was taken advantage of by some PSU manufactures who would only suggest their own models. Despite this, there are still some good power supply calculators created by those companies, so they are included in this list.

There are a few other key areas where these calculators don’t offer precise guidance. In fairness, it isn’t their job to do this.

This includes information such as the physical dimensions of a PSU. When building a PC, you should be aware that the PSU will probably occupy the largest amount of space inside your rig, so you need to take that into consideration.

With that said, PC case manufacturers were also aware of this, so most modern cases include a dedicated PSU space.

However, having space for the PSU is only one part of the equation. You also need to be aware that the PSU generates heat. When added to all the other hot components inside the case, airflow is very important to keep in mind.

Another aspect to consider is the different types of power connectors. With the release of the RTX 3000 series, we have now seen a 12-pin GPU connector. However, for now, this is just an adapter, not a cable that is provided with PSUs.

These are just some of the things worth paying attention to when choosing a PSU, but that doesn’t mean power supply calculators are not worthwhile. In fact, they are still a really good solution for this issue and should definitely be used when building a new PC or upgrading your existing one.

Related:What Power Supply Do I Have?

Let’s take a look at some of the best power calculators out there.



What makes OuterVision interesting is that it is dedicated exclusively to calculating your computer’s power consumption. As such, it will usually yield the best results. One of the great things about this calculator is that it will automatically find the best PSU and provide a link to buy it on Amazon.

This website has an almost perfect interface. It’s very easy to use, offers a wide range of options, and there are two separate PCU calculators, one for experts and another for beginners.

Another cool thing about this calculator is that it provides overclocking calculations as well. If you know from the start that you are going to overclock your components, this is the perfect tool for you.


PC Part Picker

Although the name doesn’t mention it, PCPartPicker is actually a really good power calculating website, especially if you have any prior experience.

As the name suggests, they deal primarily with choosing new parts for your PC. This can be a great tool when building a PC for the first time.

As it is not purely a power calculator, it offers plenty of other advantages, such as a compatibility check between the different parts of your computer. This is extremely useful, as ensuring all your components are compatible is one of the most challenging tasks when building a PC.

However, to help you pick the best PSU, you first have to choose a PSU and then the website tells you whether or not it’s compatible. This means you might feel a bit lost if you don’t already have knowledge and experience in PC building.



This is a very well-known name among computer enthusiasts. You might have heard of it because it offers great deals on PC components (among other things) and it also offers an excellent PC building tool.

Although this PC component picking tool isn’t as good as, for example,, it’s still probably one of the top 3 online solutions.

The issue with their PSU calculator is that it’s relatively rudimentary and doesn’t account for additions like fans or peripherals. Admittedly, these aren’t significant power consumers, but it would still be nice to have them taken into consideration.

Newegg only shows the recommended wattage, which is still positive, but the problem comes with the suggested PSUs that are offered when you calculate the necessary power consumption.

For example, if their calculator tells you that your computer requires 595 Watts and you click on the ‘Show PSUs’ button, you will be taken to their search page with PSU parameters already inputted. However, those parameters will be ‘500-599W’ so you might be shown a 500W power supply when your power requirement is 595W.


PC-Builds is a unique website in that it doesn’t offer to build a whole PC from the parts you choose (ironic, given its name), but it also isn’t just a PSU calculator.

They offer tools such as a bottleneck calculator or a ‘Can You Run It?’ calculator which will tell you if your PC can handle any game you want to play.

The calculator interface itself isn’t as straightforward as the one from OuterVision, but it is still pretty good compared to most others. One great feature is that you receive a full pie chart breakdown of how much power each component is using.

The biggest downside of this website is that it only calculates how much power you will need and does not recommend specific PSU models.



If your first thought is that this is a PSU brand, you’re right. However, they also offer a pretty nifty tool on their website to help you calculate exactly how much power your PC will require.

In fact, their power calculating tool is likely on par with the best power calculators out there, but the one obvious downside is that it only suggests Seasonic PSUs. Depending on how you look at it, this might not be so bad as Seasonic is a pretty reliable PSU manufacturer. However, as PC building enthusiasts, we like to have as many options as possible.

be quiet!

be quiet!

This is another brand-based calculator that will offer you a basic approach. This isn’t necessarily a bad thing as you can effectively calculate all your power needs, but it would still be better if you had the option to select additional power consumers.

As with Seasonic, you will only receive suggestions of PSUs from their brand. Again, as ‘be quiet!’ is a pretty good PSU manufacturing company, you shouldn’t be too concerned.

Cooler Master

Cooler Master

Power supply calculators from brands aren’t necessarily a bad thing. In fact, the solution offered by Cooler Master is definitely as good as some independent calculators, and perhaps even better than others.

The options are relatively basic, but they offer a really cool feature that allows you to customize which PSU you want after the recommendation is made. You can select the type of cable management you have in mind and the sort of efficiency rating you’re looking for.

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Aleksandar Cosic
Aleksandar Cosic

Alex is a Computer Science student and a former game designer. That has enabled him to develop skills in critical thinking and fair analysis. As a CS student, Aleksandar has very in-depth technical knowledge about computers, and he also likes to stay current with new technologies.