Best PC Power Supply Calculators

Building a new PC is a task that presents many challenges, but getting 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 what are the best ones out there.

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

The issue here is much deeper than that and getting the proper PSU for your computer should be considered as important a choice as getting the right GPU or CPU. Just like with those, there are tiers that relate to both price points, but quality and capability are what you should look for.

In the old days (well, maybe ten or fifteen years ago), it was up to the would-be PC builder to manually calculate how much power their new gaming rig would need. You would have to sum up the usage of the graphics card and the processor and RAM and fans… It was a tedious job.

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Enter Power Supply Calculators

Luckily, some really smart people came up with a cool solution – a power supply calculator. Nowadays, we can simply enter the models of each component we plan to have inside our computer to get an exact figure of how much power it requires.

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

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

There are a few other key domains in which these calculators don’t offer precision, but then again, it’s not their job to do this.

We’re talking about stuff like the physical dimensions of a PSU. When building a PC, you should be aware that the PSU will probably take the biggest part of your rig, so you need to take space into consideration as well.

Of course, PC case makers were aware of this, so most modern cases have a dedicated PSU space.

However, the room for the PSU is only one part of the equation. You have to be aware that the PSU does generate heat. Adding to all other hot components inside the case, airflow is an important thing to consider.

Another aspect to keep in mind is the types of power connectors. With the release of the RTX 3000 series, we now have a 12-pin GPU connector, but for now it’s just an adapter, not a cable that comes with PSUs.

Those are just some of the things worth paying attention to when getting a PSU, but that doesn’t mean that power supply calculators are not worthy. The fact of the matter is that they’re still a really good solution for this issue and should definitely be used when building a new PC or upgrading your old one.

Related:What Power Supply Do I Have?

Let’s see what are some of the best power calculators out there.



What’s interesting about OuterVision is that it is exclusively dedicated to calculating your computer’s power consumption. As such, it’s bound to yield the best results. The great thing about this calculator is that it will automatically find the best PSU and the link to buy it on Amazon.

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

Another cool thing about this calculator is that it offers overclocking calculations as well. So if you know from the start that you’re going to overclock your components, this is the perfect tool for you.


PC Part Picker

Although the name doesn’t sound like it, and especially if you have any experience with this website, PCPartPicker is actually a really good power calculating website.

Of course, as the name suggests, they mainly deal with choosing the new parts for your PC. This can be a great tool when building it for the first time.

Seeing how they’re not purely a power calculator, they offer plenty of other advantages, such as a compatibility check between the different parts of your computer. This is highly useful as making sure 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 choose a PSU and then the website tells you if it’s compatible or not. This means that you might feel a bit lost if you don’t already have knowledge and experience in PC building.



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

Although this PC building component picking solution isn’t as good as, for example,, it’s still probably among the top 3 best online solutions.

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

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

Basically, if their calculator tells you your computer requires, for example, 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 offered a 500W power supply when the power requirement you need is 595W.


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

They offer stuff like a bottleneck calculator or a ‘Can You Run It’ calculator which tells you if your PC can handle any game you want to play.

The calculator interface itself isn’t as straight-forward as the one from OuterVision, but it’s still pretty good compared to others. The great thing about it is that you get a full pie chart breakdown of how much power each component is using.

The biggest downside of this website is that they only calculate how much power you will need and do not recommend a specific PSU model.



If your first thought is that this a PSU brand, you’re right. In addition, however, they offer a pretty nifty tool on their website to help you calculate exactly how much power your PC is going to need.

In fact, their power calculating tool is probably on par with the best power calculators out there, but one particularly unpleasant downside is that it only suggests Seasonic PSUs. Of course, depending on how you look at it, this may not be so bad as Seasonic is a pretty good PSU manufacturer, but 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 a bad thing as you can pretty much calculate all your power needs, but it would still be better if you had the option to select additional power consumers.

Much like with Seasonic, you will only get suggestions of PSUs from that brand, but seeing how ‘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 maybe even better than some.

The options are pretty basic, but they offer a really cool feature that allows you to customize what 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.