DEWALT DCS391B 20V MAX Circular Saw — 6-1/2 In Blade, 5,100 RPM, Bare Tool

DEWALT DCS391B Circular Saw Review — The Brushed Saw That Refuses to Retire

There is a particular category of tool that stays on shelves for a decade because nothing has genuinely replaced it, and the DCS391B is one of them. It launched as the entry point into cordless circular sawing on the 20V MAX platform, and more than eleven thousand ratings later at 4.6 stars it is still the saw most people are pointed at when they ask which one to buy first.

It is also, in 2026, a brushed-motor tool sold alongside brushless siblings that cost more and cut faster. That tension is the whole story of this review. We looked at what it does well, what the brushless upgrade actually buys, and why the biggest thing to understand about this listing has nothing to do with the motor at all.

Quick verdict: the DEWALT DCS391B circular saw scores 8.2/10 in this SoftPickr review. It is a genuinely capable framing and sheet-goods saw at a low price, and the compromise is that you are buying decade-old brushed technology with no battery in the box.

Key Specifications

What a Cordless Circular Saw Changes on Site

The practical argument for cordless is not power, it is the cord. A corded saw needs an outlet, an extension lead, and a plan for where the cable lies relative to the cut. Every one of those is a small friction that adds up across a day, and the cable is a genuine hazard when a sheet of plywood is balanced across two sawhorses in a garage.

Cordless removes all of it. The saw comes off the bench, makes the cut and goes back, and rough-cutting a sheet down to manageable pieces stops being a production. For anyone already invested in the 20V MAX platform — a drill, an impact driver, a work light — adding a bare tool is the cheapest way to gain a capability, because the expensive part is already on the shelf.

Cutting Capacity and the 6-1/2 Inch Blade

Six and a half inches is the smaller of the two common cordless blade sizes, and it determines what the saw can do in one pass. It cuts through nominal two-by lumber at ninety degrees comfortably, handles plywood and OSB of any normal thickness, and takes on decking boards without complaint. That covers the overwhelming majority of what a DIY user and most trades actually cut.

Where it stops is depth at an angle. Bevelling towards fifty degrees reduces effective cutting depth substantially, and a 6-1/2 inch blade bevelled hard will not clear a two-by in one pass. A 7-1/4 inch saw will. If your work is framing at compound angles rather than sheet goods and straight cuts, the larger blade size is the specification to shop on.

Brushed Versus Brushless, Honestly

A brushed motor loses energy to friction at the carbon brushes and converts more of the battery into heat than a brushless one does. In practice that means fewer cuts per charge, a motor that runs warmer under sustained load, and brushes that eventually wear and need replacing. It also means a lower purchase price, and a simpler tool with fewer electronics to fail.

The honest comparison is that a brushless 20V circular saw will give roughly a third more runtime per battery and hold speed better in dense material. For someone cutting all day every day, that is decisive. For someone making a dozen cuts on a Saturday, it is a difference they will struggle to notice, and the price gap buys a second battery instead.

The Bare Tool Question

The single most important thing on this listing is four words in the title: battery not included. At its price this looks like an aggressive deal and it is not a deal at all for anyone starting from nothing, because a 20V MAX battery and charger add substantially to the total. Buyers new to the platform should be comparing kit prices, not bare tool prices.

For anyone already on the platform, the arithmetic inverts completely. The battery is a sunk cost, the charger is on the wall, and the saw is genuinely inexpensive. This is why the bare tool has stayed popular for a decade: it is the correct purchase for the large population of people who already own a DEWALT drill and want a saw that shares the pack.

Limitations and Compromises

The brushed motor is the honest headline limitation in 2026. Every serious competitor at a modest premium is brushless, with more runtime, better sustained speed under load and no brushes to wear. The DCS391B remains capable, but a buyer choosing it is choosing older technology to save money, and should do so knowingly rather than because the listing does not mention the difference.

No battery and no charger are included, which changes the effective price dramatically for anyone not already on the 20V MAX platform. The saw is excellent value as an addition to an existing tool set and mediocre value as a first purchase, and the listing price encourages exactly the wrong comparison for that second group.

At 6-1/2 inches the blade limits bevelled cutting depth in a way a 7-1/4 inch saw does not, and there is no electric brake on this model, so the blade coasts after the trigger is released. Neither is dangerous with normal technique, but both are things the more expensive saws in the same catalogue have addressed.

Blades, Brushes and Keeping It Cutting

The supplied 18-tooth blade is a framing blade and it is the wrong blade for most of what DIY users cut. A 40-tooth blade transforms the finish on plywood and cabinet-grade sheet goods, and it costs a fraction of the saw. Change it before the first fine cut rather than blaming the tool for tear-out that is entirely the blade.

Brushed motors need airflow, so keep the vents clear of sawdust and blow them out with compressed air every few months. The carbon brushes are consumable and will eventually need replacement after heavy use, which is a straightforward job and a cost brushless owners never pay. Check the shoe for square against the blade annually, because a knocked shoe is the most common cause of cuts that drift.

Who Should Buy It?

• You already own DEWALT 20V MAX batteries from a drill, driver or other tool.
• You cut sheet goods, decking and dimensional lumber rather than framing all day.
• You want to stop dragging an extension lead around for occasional cuts.
• You value a three-year limited warranty on a tool that will live in a garage.
• You want the lowest cost route into cordless circular sawing on an existing platform.

Look elsewhere if you do not already own 20V MAX batteries, because a kit including a battery and charger is the honest comparison and it changes the value calculation completely. Look elsewhere too if you cut for a living, where a brushless saw pays for itself in runtime within weeks, and if your work involves deep bevel cuts through two-by material, where a 7-1/4 inch blade is the specification you should be shopping on instead.

SoftPickr Verdict

The DEWALT DCS391B circular saw earns 8.2/10. It has stayed on the shelf for a decade because it is genuinely good at the job most people need a circular saw for. Five thousand RPM, a fifty degree bevel, keyless blade changes and a three-year warranty, at a price that is trivial for anyone already carrying 20V MAX batteries, is a proposition that has not needed improving.

The compromise is that it is a brushed tool in a brushless era, sold without a battery. Neither fact is hidden, but both are easy to skim past. For an existing platform owner making occasional cuts it remains a smart buy. For a first-time buyer comparing headline prices against brushless kits, it is not the bargain it appears to be, and that is why it takes no badge from us.

Price and availability change frequently on Amazon, and prices shown here may be out of date — check the current listing before ordering.

DEWALT DCS391B circular saw — Frequently Asked Questions

Does the DEWALT DCS391B circular saw come with a battery?

No. It is sold as a bare tool, which means no battery and no charger are in the box. That is why the price looks low. Anyone not already on the DEWALT 20V MAX platform should compare against kits that include a battery and charger, because the real cost of getting cutting is considerably higher than the listed figure.

Is a brushed motor a problem for occasional DIY use?

Not really. A brushless saw gives roughly a third more cuts per charge and holds speed better in dense material, which matters enormously to someone cutting all day and very little to someone making a dozen cuts on a weekend. The brushed motor also runs warmer under sustained load and has carbon brushes that eventually need replacing.

What thickness of material will it cut in one pass?

At ninety degrees the 6-1/2 inch blade clears nominal two-by lumber, any normal plywood or OSB, and standard decking. Bevelling reduces effective depth substantially, so a hard bevel through a two-by will need two passes or a larger saw. For deep bevel work, a 7-1/4 inch saw is the right tool.

Should the supplied blade be replaced?

For fine work, yes. The included 18-tooth carbide blade is a framing blade designed for speed rather than finish, and it will tear out plywood and veneered sheet goods. A 40-tooth blade costs a small fraction of the saw and transforms cut quality on cabinet-grade material. Keep both and swap according to the job.

Ready to buy? You can check the current price of the DEWALT DCS391B circular saw on Amazon — the listing shows live pricing and current stock, both of which move around more than the specification does. SoftPickr earns a commission on qualifying purchases at no extra cost to you.

Related Reviews

If the DEWALT DCS391B circular saw is not quite the right fit, these SoftPickr reviews cover the closest alternatives we have tested:

• DEWALT DCD771C2 20V MAX Drill Driver Review
• DEWALT DWE315K Oscillating Multi-Tool Review
• CRAFTSMAN 230-Piece Mechanics Tool Set Review