A circular saw is a powerful electric tool. You can use one to quickly cut and split sheets and studs both lengthwise and crosswise. A circular saw is one of the basic electrical tools often found in a homeowner's collection. Together with a screwdriver, electric jigsaw and sander, this provides an arsenal of electric tools that can cope with basic renovation tasks.
The circular saw you should choose depends on what you intend to use it for. Will you only be cutting studs now and then or do you also want to split thicker materials lengthways? This sets different demands in terms of how powerful the circular saw must be, and therefore how it must be constructed.
Circular saws are now available in two variants: battery-operated and mains powered. The former means that you don't have to deal with extensions and cables that limit your range and get in the way. This can be a major advantage. But the latter means that you don't have to keep track of whether batteries are charged, which in itself needn't be a problem if you have a number of electric tools from the same manufacturer. This is because the majority of manufacturers today have battery systems where different products from the same manufacturer can use the same battery, so you can share batteries between a number of machines. Battery-operated circular saws are a segment that's growing quickly as the cost of powerful batteries has plummeted in recent years – and is continuing to do so. This positive development means that battery-operated circular saws are becoming increasingly affordable and powerful as time passes. However, if you want to split thick studs, our tests show that operating times still leave a lot to be desired in the majority of the battery-operated models. So you need to think carefully about your needs before deciding what to buy.
When you choose a circular saw, you also need to consider the saw depth, both on 90 degree angles and lower. The larger the saw depth, the thicker the material it can saw through. In addition, you can reduce the saw depth if you don't want the circular saw to saw right through something, but instead to simply create an incision. It's useful if the circular saw has a riving knife, because this means that the blade doesn't risk getting stuck when you cut sheet materials and studs. When the blade gets stuck, this is called pinching, and it constitutes a safety risk, but can also damage the material you're working with.
It's also useful if the circular saw has a dust extraction system, because you can connect a workshop vacuum cleaner to it. This avoids a lot of the dust that otherwise arises when you're sawing. If you're sawing indoors, this is particularly important as it provides a better work environment. Construction dust is also very difficult to remove after a renovation project – it easily gets into nooks and crannies where it's difficult to access with a vacuum cleaner.
As mentioned above, circular saws are used for cutting and splitting timber. But if you also want to be able to start sawing in the centre of a sheet, for example to make a hole for a sink, you instead need a plunge cut saw or jigsaw. Some circular saws have plunge cut saw functionality. To achieve this, you purchase a kit for the circular saw to add the function. However, as a result of the design of the circular saw, you won't be able to get as close to obstacles such as walls as if you purchased a dedicated plunge cut saw. But you will still be able to start sawing in the middle of a sheet. You can only buy this type of rail for some models, so remember to check this when you buy your circular saw.
Other practical functions are a motor brake, which protects the motor from being damaged if the circular saw is working on very heavy tasks – this will then reduce the speed of the motor or switch it off as a safety measure. The guide rails help you to keep the circular saw perfectly straight as it cuts through the material. A laser can also be helpful. A well-placed laser beam means that you can easily follow the line you've drawn on the timber. And of course you should also check the guarantee before buying.
We carry out all of our tests ourselves and test all products as they are intended to be used in reality. Because we tested both mains and battery-operated circular saws, the tests are slightly different, although with several basic similarities. For example, we tested the saws on several different types of material of different thicknesses over a long period. We also have set performance tests where all circular saws go through the same test and are compared. Materials used for testing include fir studs, OSB sheets and façade panel. The most important factors we assessed are:
Performance: What can the circular saw cope with splitting? How much can it cut? What happens when it cuts out? How long is the battery life on a battery-operated circular saw without a load? How is the battery life affected by the load?
Ergonomics and build quality: Is the grip good? Are there any unpleasant vibrations? What materials is the machine made of?
Other factors taken into account were the accessories included, the accessories you can buy for the machine, the other functions the circular saw has and how much noise it causes in your working environment. The results from all tests were examined in relation to the price of a circular saw to determine its value for money. This is what the score reflects.
The Festool HK 55 EBQ+ is the best mains powered circular saw thanks to high accuracy and great finesse. This makes it very suitable as an all-round saw in the workshop. It works just as well at cutting and splitting boards for building your decking as for carrying out more polished work such as building a kitchen or sawing door leaves. Thanks to the plunge cut saw functionality, you can also plunge it in the middle of a board, but you do have to buy the correct rails for this. Despite the fact that this is Festool's weakest mains powered model, it can cope with a wide range of tasks – although not the very toughest ones we faced it with. For example, when we asked it to split damp 45 mm studs it cut out and switched to low revs if we pushed it too hard. We then had to let it rest for a while before it could finish off the task. This is the result of a motor stop that's intended to protect the motor. However, splitting 22 mm façade panel is no problem. Nor is cutting boards and studs.
The group is rubber-clad and sturdy, and feels stable and good quality. The entire machine is well balanced. Unfortunately no parallel guide is included, although it does have a mitre saw rail that you can clip onto the machine. This makes it easy to cut a stud without a set square or pen. You set the angle, turn a knob and then cut on the stated angle. The price may be high for a mains powered 1200 W machine, but given that you also get plunge cut saw functionality and that a wide range of accessories is available for the machine, it's truly versatile. As a straight circular saw, the score would be slightly lower, but given that it will be such a versatile addition to your toolbox, it gets extra points. However, if you don't need versatility but simply a circular saw with a lot of power, this isn't necessarily the right machine for you.
The Bosch Professional GKS 55+ GCE is a circular saw that's simultaneously versatile enough to suit both those only wanting to cut sheet materials and those who want to build kitchen cabinets and do finer work in the workshop. You simply get a lot of machine for your money. The build quality is high. The circular saw is stable and easy to operate, and doesn't feel either heavy or ungainly. The parallel guide is quite a long way forward, which means that it's easy to hit the right point of the material to be split or cut. The actual guide can be a bit fiddly to access as it's not well located and it feels a bit plasticky when we turn it. But all of the other controls are easily accessible. The saw also includes a guide rail so that you can make perfectly straight cuts. If we were to complain about anything it's that the cable could be a bit softer and more flexible.
The actual handle on the GKS 55+ gives a good grip, is rubber clad and a good size. There's also an extra handle if you want to hold it with both hands. Given the price class we'd have liked there to be a laser or lighting. But we appreciate the fact that there's an option to adjust the motor strength by means of six-step speed adjustment. We also like the generous saw depth. The GKS 55+ performs well – it goes through all of our tests without complaining. Overall this is a solid professional circular saw, although one that's a little expensive given what you get for your money.
The Ryobi R18CS distinguishes itself by how well it combines power and ergonomic design. It has what we expect from an 18 V circular saw in the budget price class. It's comfortable to hold, easy to adjust and to use for everything from simple cutting to splitting relatively thick timber. For the home DIYer, this means that it's a good all-round machine. You can cut studs and split planks on angles to build your decking.
Probably because of the performance, the battery life is slightly worse unloaded than it is for several of its competitors. Despite a large battery capacity, battery life is only 45 minutes unloaded. This isn't terrible, but it's clearly below average. On the other hand the operating time comes out as even better during tough tasks because it copes with these really well. For example, it can split a full 7.5 metres of slightly damp 45 mm stud before the battery runs out. Several of its competitors can only get half a metre into this kind of timber before the battery is completely drained. The battery indicator on the machine gives you complete insight into the battery status. The parallel guide is stable and the height setting is easy to access and adjust. We would have liked there to be a light, but the circular saw feels powerful and stable when you hold it and it delivers well given the price class. If you're looking for a battery-operated circular saw that can cope with a wide range of tasks, this is the model for you. But it's a good idea to buy an extra battery to swap with.
The Dewalt DWE550 is a powerful circular saw that does its job without complaining. It chews through everything we present it with, from splitting thick studs and façade panel to cutting planks and sheets. Other than its power, however, it doesn't feel particularly good quality in relation to its price. It lacks extra functions such as lighting. The grip is hard plastic without rubber cladding, which means that it feels slippery and cheap. The buttons and adjustment controls are a little bit cramped. The DWE550 feels more like a simple workhorse than a machine for finer work.
Unlike several of its competitors, it requires a socket spanner rather than a hex key to change the blade, and there's nowhere to store the spanner on the machine between changes. However, the motor guard is well located. This is made from metal and is easy to adjust. The parallel guide is also stable, although it's rather cramped. The circular saw also feels well-balanced. However, it's clear that this is a dedicated circular saw with a lot of power but not much range in terms of tasks it can do. We would have liked the manufacturer to have invested a little more in the machine's build quality and functions to make it more in line with the price. The DWE550 is most suitable for tougher tasks such as cutting sheet materials, but not so good for tasks that require precision, such as building kitchens.
The Bosch PKS 18 Li is a compact, light and thus easy to use circular saw with two really good functions. The first is the quick stop, which means that the blade stops immediately you release the button, something that's very useful from a safety viewpoint. The other is the guide plate at the front, which means that you can quickly and easily see where you should start sawing. This is very handy and gets a lot of use. However, we don't like the fact that the construction of the machine feels so thin. The circular saw also becomes a bit wobbly when we adjust the blade depth so that it only saws a little – you get a gap between the table and the saw. Setting the height is easy, though, because the screw for this is accessible. It's also easy to set the parallel guide and handle the blade guard. Changing the blades is also straightforward, although we'd have preferred the button for locking the blade to be bigger and better positioned.
Bosch describe the PKS 18 Li as a powerful circular saw, but we have another view. It's fine if you only intend to cut the odd stud and thin sheet of material now and then, but if you regularly need to split studs or build decking you need more power. For example, when we try splitting a slightly damp 45 mm stud lengthways, the machine comes completely to a stop after only half a metre – the machine goes from full to flat on this one task. Nor can it cope with splitting a 22 mm panel. Unloaded, however, the PKS 18 Li has a reasonable battery life, as it lasts for 45 minutes. This tells us that this battery-operated circular saw is OK for simple tasks, but unfortunately not much use for the home DIYer. That's a shame because it's got a nice rubber clad grip and is a handy size.
The Einhell TE-CS 18 Li is a compact battery-operated circular saw with a front light and relatively small but comfortable rubber clad grip. It's easy to use because the machine is well balanced. It's also easy to change the blade, and the button to lock the blade while you change it is easily accessible and is a good size. In purely construction terms, the TE-CS 18 Li is relatively thin, and you can tell from the build quality that this is a budget class circular saw. The cutting depth when cutting on an angle is ample and the button for adjusting the guide is quite easy to access. However, the height is tricky to adjust as the control is a little cramped.
In terms of performance, this circular saw can handle cutting studs and OSB sheets, but nothing more complicated than that. Unloaded, the battery we tested last for 30 minutes (however, the machine is sold without a battery and you can buy batteries of between 1.5-5.2 Ah). When we tried to split a slightly damp 45 mm stud in two with a fully charged battery, the battery drained only half a metre into the stud. Nor can it cope with splitting a 22 mm panel. We also found that it had to work hard when cutting thicker sheets. If you're looking for a battery-operated circular saw that you can use as an all-round machine at home, you need to look for a more powerful option. However, if you only want to cut thin sheets and studs, we think that this is a relatively good value for money machine, although without being impressive.