NEMA 23 vs NEMA 34 CNC: Which Stepper Motor (2026)

Side by side

Example figures are manufacturer rated, as published on each listing and collected 18 October 2026. The NEMA 34 listing states torque as 1200 oz-in in the title and 1204 oz-in in the bullets; both are shown.

Torque: the headline difference

Both listings state holding torque clearly, so this is a fair head-to-head. The STEPPERONLINE NEMA 23 lists 3 Nm, or 425 oz-in. The HobbyUnlimited NEMA 34 lists 8.5 Nm, or 1204 oz-in in the bullets and 1200 oz-in in the title, roughly three times the NEMA 23 figure. On stated torque alone, the NEMA 34 side wins decisively: it is the motor for gantry axes, Z axes with heavy spindles and machines where missed steps would ruin work. The NEMA 23’s 3 Nm suits lighter axes on desktop routers and small mills where the load stays modest.

Size and weight

The NEMA 23 listing is precise: a 2.24 by 2.24 inch face, 4.45 inches long, weighing 3.7 pounds. The NEMA 34 listing states 118 mm of length and 3.6 kg of weight, with no face dimensions given. The pattern is the expected one: the NEMA 34 motor is substantially bigger and more than twice as heavy. That weight matters on a moving gantry, where every extra pound is mass the other axes must accelerate, and it matters for mounting, since a NEMA 34 needs a NEMA 34 mount and the space to fit it.

Electrical: current, voltage and speed

The NEMA 23 listing states a rated current of 4.2 A with 0.9-ohm resistance, 36 volts and a 1.8-degree step angle, 200 steps per revolution, on 4 wires. The NEMA 34 listing states 6 A, voltage as “36 volts, 500 volts”, 100 watts and a speed of 100 rpm, with no step angle or wiring given. The 6 A rating means the NEMA 34 needs a driver rated for that current, a step up from what drives the 4.2 A NEMA 23. Treat the NEMA 34’s “36 volts, 500 volts” as ambiguous and the 100 rpm as the listing’s stated figure; neither is explained further.

What the listings leave out

The STEPPERONLINE NEMA 23 listing is the complete one here: torque, dimensions, weight, current, resistance, step angle, wiring and speed are all stated. The HobbyUnlimited NEMA 34 listing gives torque, current, length and weight, and leaves the rest unclear: no step angle, no wiring, no face dimensions, no mounting detail. Neither listing names a driver or states a warranty. The information gap is itself a buying factor: the NEMA 23 listing lets you verify the motor fits your build before ordering, while the NEMA 34 listing asks you to trust the torque figure.

NEMA 23 vs NEMA 34 CNC: which to buy

Choose the NEMA 23 if

• Your machine is a desktop router, small mill or lathe with light axes.
• You want every spec stated before you buy: 3 Nm, 4.2 A, 2.24-inch face, 3.7 lb.
• Your drivers are sized for 4.2 A motors.
• Gantry weight matters and 3 Nm covers your axis loads.

Choose the NEMA 34 CNC if

• Your machine has heavy axes, a big spindle or a gantry that needs 8.5 Nm.
• You have NEMA 34 mounts and the space for a 118 mm, 3.6 kg motor.
• Your drivers handle 6 A.
• You accept a thinner spec sheet in exchange for the torque figure.

Buying advice: read the listing, not just the torque

Torque wins the headline, but the spec table decides whether the motor fits your build. Start with the STEPPERONLINE NEMA 23, because its listing shows what a complete one looks like: the title gives 114mm and 3 Nm with 425 oz-in, the bullets add the 2.24 by 2.24 inch face, 4.45 inches of length, 4-wire bipolar wiring, a 1.8-degree step angle with 200 steps per revolution, 4.2 A rated current and 0.9-ohm resistance. The spec table adds a 1000 rpm speed figure, 3 watts of horsepower, alloy steel, aluminum, copper and metal construction, and the model number 23HS45-4204S. Every number you need to size a driver, check a mount and estimate the load sits in one place.

Now the HobbyUnlimited NEMA 34, where the buying advice is caution. Its listing states 8.5 Nm, 1204 oz-in in the bullets and 1200 oz-in in the title, 6 A, 118 mm of length and 3.6 kg, with 100 watts and 100 rpm. That is the whole story: no step angle, no wiring, no face dimensions, no mounting detail. The voltage reads “36 volts, 500 volts”, which the listing never explains. When a listing leaves that much unstated, budget time to confirm the frame, shaft and mounting with the seller before you order, because a NEMA 34 that does not fit your mount is a paperweight.

Finally, match the motor to the axis, not to the biggest number. The NEMA 23’s 3 Nm at 3.7 pounds suits desktop routers, small mills and lathes with light axes; the NEMA 34’s 8.5 Nm at 3.6 kg suits heavy gantries and Z axes carrying big spindles. Many builders mix the two: NEMA 34 where the load demands it, NEMA 23 everywhere else, with each driver matched to its motor’s current, 4.2 A and 6 A here. Torque you cannot mount is torque you cannot use.

FAQ: lasers and CNC

What does NEMA 23 vs NEMA 34 mean?

It is the motor frame size. The NEMA 23 listing here shows a 2.24 by 2.24 inch face; NEMA 34 is the larger frame. Bigger frame generally means more torque and more weight, which these two listings confirm: 3 Nm at 3.7 lb against 8.5 Nm at 3.6 kg.

How much stepper torque does a CNC router need?

It depends on axis load, screw or belt drive, and cutting forces. The two examples here illustrate the spread: 3 Nm for light desktop axes and 8.5 Nm for heavy gantries. Size the motor to the axis, not to the machine’s brand.

Can I mix NEMA 23 and NEMA 34 motors on one machine?

Yes, with drivers matched to each motor’s current: 4.2 A for the NEMA 23 example here and 6 A for the NEMA 34. Many builders run NEMA 34 on the heavy Z axis and NEMA 23 elsewhere.

Why does the NEMA 34 listing show 100 rpm?

That is the speed figure the listing states. Stepper motors are normally compared on holding torque rather than speed, and this listing’s torque figure, 8.5 Nm, is the number that matters for sizing.

What driver do these motors need?

Neither listing names a driver. Match the driver to the rated current: 4.2 A for the NEMA 23 and 6 A for the NEMA 34, with voltage to suit your supply.

Related: the stepper motor vs servo motor CNC comparison, the closed loop vs open loop stepper CNC guide, and the CNC mill vs CNC router comparison.