How to read a power tool spec sheet

Torque is the twist a tool puts on the bit. Drills and impact drivers publish it in inch-pounds; impact wrenches publish it in foot-pounds. Twelve in-lbs make one ft-lb, so a 1,200 in-lb drill is a 100 ft-lb drill, and a wrench rated in the hundreds of ft-lbs is not being out-muscled by a driver rated in the thousands of in-lbs.

Across the 11 hammer drills that publish a plain max-torque figure, ratings run from 530 in-lbs on the Makita XPH12 18V LXT Compact Brushless Hammer Drill to 1,590 in-lbs on the Makita GPH03 40V Max XGT Hammer Drill, with a median of 1,250 in-lbs. The 11 impact drivers run from 1,590 in-lbs on the Makita 18V LXT XDT19 Impact Driver to 2,500 in-lbs on the DeWalt DCF860 Impact Driver and the Flex FX1371A Quick Eject Impact Driver, with a median of 1,950 in-lbs. Those are not two readings of the same thing. A drill's torque is continuous twist, and your wrist is the other end of it. An impact driver's is the peak of thousands of hammer blows a minute, and the anvil soaks up the reaction. Put a big hole saw on a 2,000 in-lb impact driver and on a 1,200 in-lb drill, and the drill wins.

The 8 drill/drivers run from 800 in-lbs on the Ridgid 18V R86114 Drill/Driver to 1,590 in-lbs on the Makita 40V XGT GFD03 Drill/Driver, with a median of 1,330 in-lbs.

No maker publishes the test behind its figure, and none is held to a common one. Compare torque inside one brand's lineup with confidence and across brands in broad bands only. The number doesn't track price, either: the lowest impact-driver figure here belongs to the Makita 18V LXT XDT19 Impact Driver, which at ~$220 costs more than the median impact driver in the catalog.

The DeWalt DCD1007 20V Max XR Hammer Drill publishes “2,100 in-lbs (rated max brake torque)”. That qualifier names a different rating from a plain max-torque figure, so it is left out of the ranges above rather than guessed into them.

Then there's DeWalt's UWO, “unit watts out”, and its newer MWO, “max watts out”. They are DeWalt's own measure of power at the output, taken under DeWalt's own conditions; Craftsman, a sister brand under Stanley Black & Decker, uses UWO too. Nobody else does, and neither publishes a conversion to torque, so this site prints UWO exactly as published and never converts it. 4 tools publish a watts-out figure and no torque at all: the Craftsman V20 BRUSHLESS RP CMCD726 Hammer Drill, the DeWalt FlexVolt DCS578 Circular Saw, the DeWalt 20V Max XR DCD801 Drill/Driver and the Craftsman V20 Brushless RP CMCD725 Drill/Driver. The DeWalt DCD805 20V Max XR Compact Hammer Drill and the DeWalt DCD1007 20V Max XR Hammer Drill publish both, and the pair shows why: the DeWalt DCD805 20V Max XR Compact Hammer Drill lists 796 in-lbs beside 850 UWO. Two separate numbers, not one number in two units.

Grinders sometimes skip torque for wattage or a “corded equivalent” amp rating. Treat both as the maker's claim about its own tool. Neither is measured the same way by any two brands.

Every speed on a spec sheet is no-load: the bit spinning in air. Put it in oak and it drops. It's still the fairest speed figure to compare, because spinning in air is the same test for everyone, and it caps what the tool can do.

Drills trade speed for torque through a gearbox. 20 of the drills here have two speeds and 3 have three. Low gear is for hole saws, augers and lag bolts; high is for small twist bits. Top speeds run from 1,700 RPM on the Milwaukee 3602 M18 Compact Brushless Hammer Drill to 3,000 RPM on the Flex 24V FX1272T Turbo Hammer Drill, with a median of 2,100 RPM. The Flex 24V FX1272T Turbo Hammer Drill's top figure is a boost mode, labeled as such on its spec sheet.

Impact drivers have no gearbox to shift, just a trigger and a mode button. Their top speeds run from 2,900 RPM on the Ryobi ONE+ HP PBLID02 Impact Driver to 4,000 RPM on the Flex FX1371A Quick Eject Impact Driver, with a median of 3,400 RPM.

Saws and grinders care about speed more than torque, because the edge speed of the blade is what cuts. Circular saws here run from 4,300 RPM on the Ryobi ONE+ HP PBLCS300 Circular Saw to 6,000 RPM on 4 tools, the Makita 40V XGT GSH02 Circular Saw among them, with a median of 5,800 RPM. Grinders run from 8,500 RPM on 4 tools, the Makita 40V XGT GAG04 Angle Grinder among them, to 10,000 RPM on the Metabo HPT MultiVolt G3612DVE Angle Grinder and the Flex 24V FX3171A Variable Speed Angle Grinder, with a median of 9,000 RPM, and 3 of them offer variable speed. That's worth having for wire cups, flap discs and anything that gets hot. One rule isn't optional: a wheel's printed maximum RPM must be at or above the grinder's no-load speed. On a 10,000 RPM grinder, a wheel rated lower can come apart.

In hammer mode, two ridged discs inside the gearbox ride over each other as the chuck turns, knocking the bit forward thousands of times a minute. Blows per minute is how many. It turns a drill into something that will put a 3/16 in hole in concrete for a Tapcon or a sleeve anchor. It does nothing in wood or steel, and you should switch it off there.

Across 13 hammer drills the rate runs from 25,500 BPM on the Milwaukee 3602 M18 Compact Brushless Hammer Drill to 48,000 BPM on the Flex 24V FX1272T Turbo Hammer Drill, with a median of 33,000 BPM. BPM is only half the story, because the blows are small. There's no published figure for how hard each one lands.

That's the ceiling. Occasional anchors and the odd 1/2 in hole in block are hammer drill work. A day of it, or anything bigger, belongs to an SDS rotary hammer, which uses a piston to hit far harder and publishes impact energy in joules instead of a blow count. Hammer drill or plain drill/driver.

An impact driver spins freely until the fastener resists. Then an internal hammer starts striking the anvil the bit sits in, turning it a little further with every blow. Impacts per minute counts the blows. That's why it can sink a 6 in structural screw without wrenching your arm, and why it's loud.

The 11 impact drivers here run from 3,800 IPM on the Makita 18V LXT XDT19 Impact Driver and the DeWalt Atomic DCF850 20V Max Compact Impact Driver to 4,500 IPM on the DeWalt DCF860 Impact Driver, with a median of 4,100 IPM. The spread is narrow, and a few hundred IPM either way is not something you'll feel.

Drive modes matter more day to day. Every impact driver in the catalog has more than one, and 3 name a dedicated mode for self-tapping or bolt work. Self-tap modes run fast until the drill point breaks through sheet metal, then slow down so the screw doesn't strip. A low mode that stops hammering early is what keeps you from snapping a trim screw or blowing through drywall paper.

Every drill here has a 1/2 in chuck. What varies more is what it's made of: 19 of 23 list a metal chuck, 16 say it ratchets, and 6 have carbide jaws or inserts. A ratcheting metal chuck locks tighter by hand and survives being dropped. Plastic-sleeve chucks are where cheap drills save money, and a round-shank bit slipping in the chuck is the first thing you notice.

All 11 impact drivers take 1/4 in hex bits in a quick-change collet, and 4 let you drop a bit one-handed. No round shanks, no chuck key. Use impact-rated bits. Standard ones shatter, because the blows twist the shank.

The numbered collar behind a drill's chuck is a clutch. Set it low and the drill slips and ratchets once a screw is seated, instead of driving it through the face of the board. Higher numbers slip later. Drill mode and hammer mode bypass it entirely.

15 drills here publish a setting count for a numbered collar. They run from 15 settings on 3 tools, the Craftsman V20 BRUSHLESS RP CMCD726 Hammer Drill among them, to 25 settings on the Bosch PROFACTOR GSB18V-1330C Hammer Drill and the Bosch PROFACTOR GSR18V-1330C Drill/Driver, with a median of 22 settings. The Makita GPH03 40V Max XGT Hammer Drill and the Makita 40V XGT GFD03 Drill/Driver replace the collar with an electronic clutch that counts its settings per gear, so they are left out of that range. The other 6 don't publish one, and the site doesn't guess one.

The count matters less than the bottom of the range: the lowest setting has to slip before a small brass screw snaps or a trim screw sinks too deep. Impact drivers have no clutch at all, which is the single best reason to own a drill/driver as well.

Head length is front-to-back, from the nose to the back of the motor housing. It decides whether a tool and a bit fit between framing. Studs 16 in on center leave a 14-1/2 in bay, and once you add a 2 in bit and a hand on the tool, every half inch of head counts.

Impact drivers here run from 3.97 in on the DeWalt Atomic DCF850 20V Max Compact Impact Driver to 5.5 in on the Ryobi ONE+ HP PBLID02 Impact Driver, with a median of 4.7 in. The 6 hammer drills that publish a length run from 5.8 in on the Milwaukee 3602 M18 Compact Brushless Hammer Drill to 7.75 in on the Makita GPH03 40V Max XGT Hammer Drill, with a median of 7.125 in.

Bare-tool weights: hammer drills from 2.3 lbs on the Milwaukee 3602 M18 Compact Brushless Hammer Drill to 4.6 lbs on the Metabo HPT MultiVolt DV36DC Hammer Drill and the Bosch PROFACTOR GSB18V-1330C Hammer Drill, with a median of 3.4 lbs; impact drivers from 2.1 lbs on the DeWalt Atomic DCF850 20V Max Compact Impact Driver to 2.7 lbs on the DeWalt DCF860 Impact Driver and the Flex FX1371A Quick Eject Impact Driver, with a median of 2.3 lbs. A battery adds a pound or more, and a big pack adds more, so weigh the kit you'll actually carry up a ladder.

A brushed motor switches current through carbon brushes rubbing on a commutator. They wear, spark, and waste energy as heat. A brushless motor switches electronically, so nothing wears, more of the battery ends up at the bit, and the same electronics make drive modes and kickback sensing possible.

Every one of the 74 tools in this catalog is brushless, so here it's table stakes rather than a feature. The split that matters now is between a brand's own tiers. Milwaukee's Fuel line against its standard brushless tools, or DeWalt's XR against its Atomic compacts. Both tiers are brushless; the premium one gets the bigger motor and the better electronics. Brushless or brushed.

A lithium-ion cell sits at about 3.6 volts nominal and about 4 volts fresh off the charger with nothing connected. Stack five in series and you get 18V nominal, 20V at rest. Makita, Milwaukee, Ryobi, Bosch and Ridgid print the first number. DeWalt and Craftsman print the second and call it “20V Max”; DeWalt's own small print says the nominal voltage is 18. Same cell count, same class of tool.

51 of the 74 tools here run on five-cell 18V or 20V Max packs. The rest step up:

Flex's 24V pack is six cells (21.6V nominal). Makita's 40V Max XGT and Metabo HPT's 36V MultiVolt are ten cells, 36V nominal, labeled two ways. Makita's “18V X2” tools take two ordinary 18V packs at once. DeWalt FlexVolt packs rewire themselves: 20V Max in a 20V tool, 60V Max in a FlexVolt one.

Higher voltage lets a tool draw the same power at less current, which runs cooler and suits saws and grinders. It doesn't make a drill better at drilling 3/8 in holes. The full 18V vs 20V Max answer.

Amp-hours measure how much charge a pack holds. Multiply by nominal voltage for watt-hours, the real fuel gauge: a 5.0Ah 18V pack is 90 Wh. More amp-hours usually means more cells in parallel, which is why a 5.0Ah pack is heavier than a 2.0Ah pack. It's also why it can deliver more current, so a saw bogs less on a big pack.

Each brand's high-output packs (bigger 21700 cells, or tabless and pouch cells in the newest lines) matter most on high-draw tools like circular saws and grinders. On an impact driver, a compact 2.0Ah pack is the better pick for your wrist.

The batteries are also what you're committing to. You can buy one drill from any brand, but once you own three packs and two chargers you've married a battery platform, and the next tool will be that color. Packs don't cross brands, and a third-party adapter can void the tool warranty. Across the 50 tools here sold both bare and as a kit, the kit costs a median of ~$100 more. That's roughly the price of the batteries and charger you're buying into. Compare the 10 platforms.

One practical limit: under FAA rules a spare lithium-ion pack flies in carry-on only, up to 100 Wh each, or up to two packs of 101 to 160 Wh with the airline's approval, and nothing larger. A 12.0Ah 18V pack is 216 Wh.

Every circular saw here takes a 7-1/4 in blade, the framing standard, so blade size doesn't separate them. Cut depth does, a little. Dimensional lumber is 1-1/2 in thick, so any 7-1/4 in saw clears a 2x square with room to spare; the extra depth matters on doubled 2x, on stair stringers, and when you're cutting on a guide rail that eats some capacity.

Depth at 90° runs from 2-3/8 in on the Makita 40V XGT GSH02 Circular Saw to 2-5/8 in on 3 tools, the Milwaukee M18 Fuel 2834 Circular Saw among them, with a median of 2-9/16 in. Only 2 saws publish a 45° depth, from 1-3/4 in on the Ryobi ONE+ HP PBLCS300 Circular Saw to 2-1/16 in on the Milwaukee M18 Fuel 2834 Circular Saw. At 45° you need at least 1-1/2 in to finish a 2x in one pass.

The arbor, the hole in the blade, is 5/8 in on 7-1/4 in saws, so blades cross brands freely. That's one of the few things that does.

Bevel is how far the saw tilts on its shoe for an angled cut. 45° is the one everyone needs; past it is for roof framing, where rafter and hip cuts can run steeper. The detents matter as much as the maximum. A positive stop at 22.5° and 45° means you don't have to trust a protractor scale on site.

Maximum bevel here runs from 50° on the Bosch 18V ProFactor GKS18V-25GC Circular Saw to 57° on the Milwaukee M18 Fuel 2834 Circular Saw and the DeWalt FlexVolt DCS578 Circular Saw, with a median of 56°. The lowest figure isn't automatically the worst: the Bosch 18V ProFactor GKS18V-25GC Circular Saw lists “50° (full 2x capacity across range)”.

Stroke length is how far the blade travels each way; strokes per minute is how often. Longer strokes clear sawdust better and use more of the blade's teeth, so they cut wood and demo faster. Metal wants the opposite: a slower speed and a straight stroke, so the teeth don't overheat.

8 of the 10 reciprocating saws here have a 1-1/4 in stroke; the DeWalt DCS386 Reciprocating Saw and the Craftsman V20 Brushless RP CMCS351 Reciprocating Saw have 1-1/8 in. Top speeds run from 3,000 SPM on 7 tools, the DeWalt DCS386 Reciprocating Saw among them, to 3,200 SPM on 3 tools, the Ridgid 18V Brushless Reciprocating Saw R8647 among them, with a median of 3,000 SPM. That spread is small enough that stroke length and weight decide more than SPM does.

Orbital action adds an up-and-down rock to the stroke, so the blade bites on the pull and lifts on the push. It's noticeably faster through framing and pruning, and it chews up the cut. Switch it off for metal, for plunge cuts and for anything that needs a straight line.

4 of the 10 reciprocating saws here list switchable orbital action. The Makita 18V X2 LXT XRJ06 Recipro Saw states outright that it cuts straight only. If demo is the job, it's worth having; for plumbing and electrical rough-in, it rarely gets switched on.

A bigger wheel cuts deeper and wears longer. A 5 in wheel reaches about 1/4 in further into a cut than a 4-1/2 in, and it makes a heavier tool.

6 of the 10 grinders here take a 5 in wheel or larger with the right guard; 4 are 4-1/2 in only. All of them use a 5/8-11 spindle thread, which is the North American standard, so wheels, cup brushes and flange nuts fit across brands.

Check the wheel's own RPM rating against the grinder's no-load speed every time, and never run a wheel larger than the guard fitted.

An electric brake uses the motor itself to stop the spindle when you let go of the trigger, so the blade or wheel stops in a second or two instead of coasting. Kickback control uses a sensor to cut power when the tool twists suddenly, which is what happens when a drill bit or grinder wheel binds.

Every circular saw here has an electric brake. Grinders are where it varies: 7 of 10 list an electric brake and 5 a kickback brake. The Flex 24V FX3171A Variable Speed Angle Grinder, the Craftsman V20 Brushless RP CMCG451 Angle Grinder and the Ryobi ONE+ HP PBLAG02 Angle Grinder don't list an electric brake. Among drills, 13 of 23 list kickback control.

The switch matters too. 6 grinders here use a paddle switch, which stops the tool the moment you let go. 4 use a slide switch, which can lock on. A locked-on grinder that gets dropped keeps spinning. On a grinder, a paddle switch and a brake are worth more than another thousand RPM.

Impact wrenches publish two torque figures, in ft-lbs. Fastening torque is what the tool delivers tightening. Nut-busting (or breakaway) torque is the peak it reaches loosening a seized nut. Nut-busting is always the bigger number, often by a lot. Compare fastening to fastening and breakaway to breakaway; one maker's breakaway figure against another's fastening figure is how a mid-torque wrench gets sold as a high-torque one.

Fastening torque across 9 impact wrenches here runs from 275 ft-lbs on the Craftsman V20 Brushless RP CMCF921 Impact Wrench to 600 ft-lbs on the DeWalt 20V Max XR DCF891 Impact Wrench and the Flex 24V FX1451 Impact Wrench, with a median of 520 ft-lbs. Nut-busting torque runs from 590 ft-lbs on the Bosch 18V GDS18V-330CN Impact Wrench to 810 ft-lbs on the Makita 40V XGT GWT07 Impact Wrench, with a median of 740 ft-lbs.

The anvil is the square drive the socket goes on, usually 1/2 in on mid- and high-torque wrenches and 3/8 in on compact ones. It holds the socket one of two ways. A friction ring (a hog ring) is a spring band that grips the socket: fast changes, and the socket can walk off under a heavy load or overhead. A detent pin is a spring-loaded pin that clicks into the socket's hole: the socket stays put, and you need a pick or a nail to release it. Friction ring for tire and general shop work; detent pin for overhead and structural work. Every impact wrench here with a published anvil uses a friction ring. Impact wrench or impact driver.