Quick verdict
The same blade and the same cut capacity, with a big gap in power. The FlexVolt DCS578B rips wet pressure-treated 2x12 without slowing; the 20V DCS570B cuts deck boards and dry 2x well and labors on wet joists. If FlexVolt packs are in the shed, the 578 is the saw. On 20V packs alone, the 570 is the sensible buy.
DeWalt DCS578B FlexVolt 60V MAX 7-1/4 Inch Circular Saw
The DCS578B is the FlexVolt 60V MAX 7-1/4 inch circular saw with a brushless motor, 5,800 RPM, an electric brake, a 2-9/16 inch depth of cut and a 57 degree bevel. It cuts like a corded saw through wet pressure-treated lumber and runs on FlexVolt packs, which also power DeWalt chainsaws and mowers.
DeWalt DCS578B FlexVolt 60V circular saw versus DeWalt DCS570B 20V MAX circular saw: power, speed, cut capacity, battery platform and price compared for deck and fence work.
The picks at a glance
| Tool | Best for | Score /100 | |
|---|---|---|---|
| DeWalt DCS578B FlexVolt 60V MAX 7-1/4 Inch Circular Saw | Best for Framing and Wet Lumber | 9.1 | Check price |
| DeWalt DCS570B 20V MAX 7-1/4 Inch Circular Saw | Best Value 7-1/4 Inch Saw | 8.6 | Check price |
The picks, reviewed
DeWalt DCS578B FlexVolt 60V MAX 7-1/4 Inch Circular Saw
The DCS578B is the FlexVolt 60V MAX 7-1/4 inch circular saw with a brushless motor, 5,800 RPM, an electric brake, a 2-9/16 inch depth of cut and a 57 degree bevel. It cuts like a corded saw through wet pressure-treated lumber and runs on FlexVolt packs, which also power DeWalt chainsaws and mowers.
Reasons to buy
- Corded-class power for wet 2x lumber
- FlexVolt packs run chainsaws and mowers
- 5,800 RPM with brake
- Full 7-1/4 inch blade
Reasons to avoid
- Needs FlexVolt packs, which cost more
- Heavier
- More saw than deck boards need
DeWalt DCS570B 20V MAX 7-1/4 Inch Circular Saw
The DCS570B is the 20V MAX 7-1/4 inch circular saw with a brushless motor, 5,200 RPM, an electric brake, 2-9/16 inch depth of cut and a 57 degree bevel. It runs on standard 20V packs and handles deck boards, fence rails and 2x framing at a lower price than the FlexVolt.
Reasons to buy
- Runs on every 20V MAX pack
- Same blade, depth and bevel as the FlexVolt
- Lighter
- Lower price
Reasons to avoid
- Slows in wet pressure-treated 2x
- Drains small packs quickly
- Less reserve for repeated rips
Where these two differ
Both are 7-1/4 inch brushless DeWalt circular saws with an electric brake, the same depth of cut and the same 57 degree bevel. The DCS578B runs on FlexVolt 60V packs and spins at 5,800 RPM with the power of a corded saw. The DCS570B runs on 20V MAX packs at 5,200 RPM with the power of a good cordless saw. The difference shows in wet pressure-treated lumber and in the price of the packs.
This comparison is based on the published specifications and manuals for both saws and on recurring owner feedback. We have not run either saw ourselves.
| Specification | DCS578B | DCS570B |
|---|---|---|
| Platform | FlexVolt 60V MAX | 20V MAX |
| Speed | 5,800 RPM | 5,200 RPM |
| Blade | 7-1/4 inch | 7-1/4 inch |
| Depth at 90 | 2-9/16 inch | 2-9/16 inch |
| Bevel | 57 degrees | 57 degrees |
| Brake | Electric | Electric |
Power in wet lumber
Pressure-treated joists and beams arrive wet and heavy. The FlexVolt saw rips a 2×12 without slowing and crosscuts a 4×4 in two passes with reserve. The 20V saw cuts the same lumber but slows in the rip and drains a 5 Ah pack in a short afternoon of joists. On dry deck boards and fence rails both cut cleanly.
Weight and handling
The 20V saw with a compact pack is the lighter of the two and easier on a ladder trimming fence posts. The FlexVolt saw with its pack is heavier and better planted on a sawhorse.
Batteries and runtime
FlexVolt packs cost more and also run the DeWalt chainsaw, mower, blower and table saw, which is the argument for the 578 in a yard. 20V packs are plentiful and cheap; a FlexVolt pack also works in the 570 as a 20V pack with long runtime.
Blades and setup
Both take any 7-1/4 inch blade with a 5/8 inch arbor. A 24-tooth framing blade suits joists on either; a 40-tooth blade gives cleaner deck board ends. Both set depth with a rear lever and bevel with a front scale.
Yard jobs this decides
A deck with pressure-treated framing favors the 578. A fence of rails and pickets, a raised bed, a shed with dry lumber and a run of deck boards suit the 570. A homeowner already on FlexVolt for a chainsaw gets the 578 for little extra.
Common owner complaints
DCS578B owners mention weight and pack cost. DCS570B owners mention runtime on small packs and slowing in wet lumber. Neither has a reliability pattern.
Which one should you buy
Buy the DCS578B if FlexVolt packs are in the shed or wet framing is the job. Buy the DCS570B for deck boards, fences and dry lumber on 20V packs.
Our verdict
The DeWalt DCS578B takes this comparison on power. The DCS570B is the better value for a homeowner cutting dry lumber on 20V packs.
How we research
This comparison is built from the published specifications, manuals and warranty terms of both products and from recurring owner feedback. We have not run either product ourselves; where the makers do not publish a figure we say so rather than guess.
What to look for
Lumber
Wet pressure-treated 2x favors the FlexVolt. Dry deck boards suit the 20V.
Packs
FlexVolt packs cost more but run chainsaws and mowers too.
Weight
The 20V saw is lighter for fence work on a ladder.
Price
The DCS570B is cheaper bare and in kits.
Our verdict
The same blade and the same cut capacity, with a big gap in power. The FlexVolt DCS578B rips wet pressure-treated 2x12 without slowing; the 20V DCS570B cuts deck boards and dry 2x well and labors on wet joists. If FlexVolt packs are in the shed, the 578 is the saw. On 20V packs alone, the 570 is the sensible buy.
FAQs
Yes, a 7-1/4 inch blade with the same depth of cut at 90 and 45 degrees.
Yes, slowly, and it drains a small pack doing it. The DCS578B cuts it like a corded saw.
Yes; FlexVolt packs work as 20V packs in any 20V tool and give the 570 longer runtime.
The DCS570B handles the boards; the DCS578B handles the joists and beams. A builder with both packs picks the 578.
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