Milwaukee M12 Fuel 3403-20 Drill Review

Milwaukee 3403-20 Angle 5

Quick take

The Milwaukee M12 Fuel 3403-20 is a fantastic all-around drill that is perfectly sized and powered for around the home and for professionals needing a dedicated light-duty drill. The footprint is svelte, it is exceptionally lightweight, and it’s one of the fastest drills in the 12V category. The build quality and warranty also stand out. However, there is no hammer drill functionality, and it can’t compete on speed and power with most 18V drills. Milwaukee’s flagship Fuel-branded drills are also expensive, although the premium price is warranted if you value the performance and quality. Even with all the pros, it may be best for most people to skip buying the 3403-20 in favor of the Milwaukee M12 Fuel 3404-20 Hammer Drill, which is the same drill but includes a hammer drill mode.

Brand Milwaukee
Platform M12 Fuel
Motor Brushless
Speeds 2
Torque in-lbs 400.0
Clutch settings 13
Chuck size 1/2"
Same as M12 gen 3 drill

Global rankings

18 models tested

Drilling speed (sec.)25.113
Driving speed (sec.)16.213
Torque (in-lbs)400.010
Bare weight (lbs)2.103
Drilling Noise (dBA)84.16

Editorial opinion

Methodology used: Light duty

Editorial rating

3.79 / 5 stars


  • Exceptionally compact and lightweight
  • Fast drilling and driving performance in its class
  • Solid build quality
  • Long warranty
  • Brushless motor


  • No hammer drilling functionality

Recommended configuration


Includes (1) M12 Red Lithium XC 4Ah, (1) M12 Red Lithium CP 2Ah battery

Series lineup

Model #PlatformAction ModesMax Torque (in-lbs)Review
Milwaukee 3403-20 (Gen 3)M12 FuelDrill only400.0Full review
Milwaukee 3404-20 (Gen 3)M12 FuelDrill, hammer400.0Full review

Lab results

Drilling speed

Drilling speed total time (drill mode, sec.): 25.1
Drilling speed average time (drill mode, sec.): 5.0
Drilling speed total time (hammer mode, sec.): N/A
Drilling speed average time (hammer mode, sec.): N/A
Hammer mode speed improvement: N/A

The 3403-20 is one of our test fleet’s fastest and most powerful 12V drills. No 12V drill has the RPMs and power to take the speed crown from flagship 18V models. But the 3403-20 is one of the few 12V drills powerful enough that we didn’t need to drop down a gear during our drilling speed test for additional torque to finish the job.

Since our drilling speed tests are designed to test the upper limits of a drill using a 1/2-inch drill bit, it’s no surprise that the 3403-20 is exceptionally fast in more typical scenarios with boring narrower holes.

We also tested a range of spade, forstner, and auger bits in various sizes to further understand the 3403-20’s limits. Only when boring holes wider than 1/2 inch did it bind up. In these cases, dropping a gear for more torque finished the task, albeit slowly, and sometimes needing to remove and reinsert the bit to clear holes.

The overall drilling performance, combined with its weight and compact footprint, explains why the 3403-20 is perfect for most tasks around the home and woodworking, which don’t push drills to their limits.

Compare drilling speed test results

Driving speed

GRK total driving time forward (sec.): 16.2
GRK average driving time forward (sec.): 3.2
GRK total driving time reverse (sec.): 10.6
GRK average driving time reverse (sec.): 2.1

The 3403-20 also impresses with its driving speed. It turned in some of the fastest driving times of any 12V models in our test fleet, explaining why it’s an ideal tool around the home that’s compact, versatile, and powerful.

Providing additional context to our driving speed test results further highlights the 3403-20’s performance. The closest competitor needed approximately ten more seconds to complete our driving speed test. This performance is astounding when comparing performance against our flagship and mid-tier 18V tested models, where the difference is a few seconds.

Compare driving speed test results


Milwaukee 3403-20 RPM Chart

Max RPM speed 2: 1,430.0
Max RPM speed 1: 425.0

We tested the 3403-20’s RPM output using a contact tachometer. The test results highlight the performance decisions Milwaukee’s product managers made to tune the drill for performance in specific tasks. The 3403-20’s tested RPM output is low, which is a head-scratcher when considering our tests’ best-in-class drilling and driving speed.

But our drilling and driving speed tests are designed to test how each drill performs at the top of its range. The 3403-20 is geared to outshine competing models in the most demanding tasks. Milwaukee is happy to give up some time in lighter-duty jobs to other drills that can’t compete on speed at the top of their range. All power tools have these performance tradeoffs.

Arguably, speed in light-duty tasks doesn’t matter for most people. For example, there’s little value to being the fastest drill when drilling 1/8-inch holes since all drills complete this task efficiently.

These tradeoff relationships explain why the 3403-20’s low RPM output isn’t a downside. It is fast when it matters most for saving time.

Compare drill RPM test results


Advertised max torque (in-lbs): 400.0
Advertised max torque (ft-lbs): 33.3

While 400.0 in-lbs of torque isn’t high compared to all drills in our test fleet, it is high for a 12V drill, which shouldn’t be surprising since the 3403-20 sits within Milwaukee’s flagship Fuel-branded lineup.

However, we don’t consider torque a critical factor when purchasing a 12V drill. Firstly, impact drivers are the preferred tool for driving tasks that rely on torque to power through a job with lots of twisting force. Next in line is an 18V drill, which is needed for heavy-duty drilling applications.

Focusing on size, weight, and RPM performance under load are more important since 12V drills are mostly used as dedicated light-duty tools for professionals or for homeowners who don’t need brute force power.

Note: We don’t currently test drill torque in-house, as we do for impact drivers using a torque meter. The torque commentary discussed here relies upon both advertised torque specifications provided by manufacturers and practical insights learned from performance in our various drilling and driving tests.

Compare drill torque


Milwaukee 3403-20 Chuck Closeup

Chuck size: 1/2″
Chuck sleeve material: Knurled metal

The 3403-20 includes a fantastic all-metal chuck that is more premium than most other drills in our test fleet. The knurled metal sleeve provides the right amount of friction on your hand for grip when tightening and loosening.

The three-jaw chuck also holds bits well since the ratcheting mechanism locks tightly onto a bit when tightening. We didn’t run into scenarios where the chuck inadvertently loosened during use.

Motor & BPM

Milwaukee 3403-20 Drill Modes

Motor type: Brushless
Action modes: Drill only
Advertised blows per min. (speed 2): N/A
Advertised blows per min. (speed 1): N/A
Variable speed trigger: Yes
Kickback control technology: No
Trigger draw length (in.): 0.375

The Powerstate brushless motor powers only a single action mode. Like all drills, the drill mode disengages the clutch and delivers the highest torque output in the low setting.

You’ll need to jump to the Milwaukee M12 Fuel 3404-20 Hammer Drill if you need a hammering functionality for efficiently drilling masonry and thick lumber.

No kickback control technology is included with the 3043-20, to be expected in the 12V category.

Compare drill motors

Clutch & speed settings

Milwaukee 3403-20 Clutch & Speed

Speed settings: 2
Clutch settings: 13

The 3403-20 has a two-speed gearbox with 13 clutch settings. All the clutch options and drill single mode can be run in the high or low-speed setting, helping to fine-tune the performance profile to the task at hand.

While 13 clutch settings are fewer than many competing drills, we don’t see it as a downside. 13 options are more than enough to precisely fine-tune the 3403-20 with the appropriate torque output to help avoid cam-out and stripped threads for any driving scenario.

Compare drill clutch and speed settings

Charging time

Milwaukee 3403-20 Fuel Gauge

Charger tested: Milwaukee M12 & M18 Multi-Volt (48-59-1812)
Charging time 2Ah battery (min.): 38.0
Charging time 4Ah battery (min.): Not tested
Charging time 5Ah battery (min.): Not tested
Charging time per Ah (min.): 19.0
Fuel gauge: Onboard tool

The Milwaukee M12 and M18 multi-volt charger (model 48-59-1812) included in most kits is reasonably fast at charging batteries, including to beat out team red’s most frequent adversary, Dewalt. It takes 38 minutes to charge an M12 2Ah battery, equivalent to 19 minutes per amp-hour.

Many Milwaukee drills come in kits with chargers that charge multiple voltage batteries in one, conveniently saving space in your shop if you have several M12 and M18 ecosystem tools.

Compare drill charging test results

Design & ergonomics

Stands upright (no battery): No
Stands upright (w/ battery): Yes
Grip material: Rubber overgrip
Magnetic holder: No
Bit holder: No
Belt hook: Yes
Lanyard compatible: No

The 3403-20 employs the same design language that Milwaukee uses throughout its Fuel-branded 12V drill and driver lineup. The forward-leaning handle and upward-angled head orient the 3403-20 in the correct plane when preparing to drill and exerting forward pressure.

Helping the ergonomics, there is a rubber overmold surrounding the grip, which improves shock absorption and gripping power.

An all-metal belt hook is included in the box and is mountable on either side of the head just behind and above the trigger. There is no onboard bit holder or magnetic fastener plate to hold screws, though these third-party add-ons can be purchased separately and attached to the 3403-20.


Milwaukee 3403-20 On Scale

Bare weight (lbs): 2.10
Weight w/ 2Ah battery (lbs): 2.49
Weight w/ 4Ah battery (lbs): Not tested
Weight w/ 5Ah battery (lbs): Not tested

The 3403-20 is exceptionally lightweight for a drill, weighing in at 2.10 lbs in its bare form. Milwaukee’s batteries are also comparably lightweight, helping to retain its light status kitted with a battery. As a result, unlike other heavier drills in our test fleet, we didn’t frequently experience hand and arm fatigue throughout our testing.

We tested different battery configurations since the working weight can differ meaningfully from the bare tool weight. We recommend combining the 3403-20 with Milwaukee’s M12 Red Lithium CP 2Ah Ah battery for a good balance of drilling performance and weight in a lightweight setup.

If weight is less of a concern, Milwaukee offers several higher Ah-capacity M12 batteries in its lineup. But you lose the seamless in-handle design for a slightly bulkier footprint and heavier weight.

Compare drill weight test results


Milwaukee 3403-20 Footprint1

Max height (in.): 8.250
Max width (in.): 2.250
Chuck to back length (in.): 6.000
Base length (in.): 2.000
Base width (in.): 2.250

You’ll be hard-pressed to find a more compact and equally powerful drill on the market. The 3403-20 is incredibly agile, with a smaller footprint in all dimensions than most drills. The size helps the 3403-20 fit well into tight spaces, vastly improving its versatility.

Compare drill footprint test results

Drilling clearance

Min. interior width clearance (in.): 7.750
Min. top edge clearance (in.): 1.250
Min. interior 45-deg. clearance (in.): 6.000

Unsurprisingly, the 3403-20 shined in our clearance tests, designed to understand how well a drill fits into areas with limited access and drills in tight spaces. The short tip-to-tail length is impressive, helping it fit easily between vertical boards and in tight corners. The head is also compact, which allows it to fit under shelves well.

Compare drilling clearance test results

Auxiliary arm

Auxiliary arm: No

The 3403-20 doesn’t include an auxiliary handle to control recoil and enhance stability during heavy-duty drilling tasks. But we don’t see this as a downside. The 3403-20 isn’t designed to tackle the heaviest-duty drilling tasks, such as drilling wide and deep holes in masonry or wood, where an auxiliary handle is helpful.


Milwaukee 3403-20 Noise Chart

Max no-load noise (dBA): 84.2
Max drilling noise (dBA): 84.1

The 3403-20 is moderately quiet when drilling under load, primarily because it doesn’t include a hammer drill functionality, which is loud.

Compare drill noise test results


Milwaukee 3403-20 Light Wall
Milwaukee 3403-20 Light Closeup

Light: Yes
Light location: Near trigger
Light positions: 1
Customizable light settings: None
Light count: Single LED
Light active time (sec.): 15.0

A single LED above the trigger brightly illuminates the drilling surface in front of the head. Unlike some Dewalt drills, there are no extra light features, such as a spotlight mode or the ability to turn off the light when pressing the trigger.


Tool warranty (years): 2-3 (depends on model)
Battery warranty (years): 5

Milwaukee stands behind the durability of its drills with exceptionally long warranties. The 3403-20 has a five-year warranty, which is among the longest offered by any manufacturer. Milwaukee’s M12 Li-Ion batteries have two or three-year warranties, depending on the specific model.

Picture of Nathan Hamilton
Nathan Hamilton
Nathan Hamilton is the founder of DIY Gear Reviews and a recognized expert in the home and DIY space. He has over 200 bylines covering topics such as power tools, hand tools, and woodworking. Nathan is the strategic director for DIY Gear Reviews, deciding everything from the content covered to designing the testing methodologies for lab-tested reviews. He can be emailed at


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