Milwaukee M12 3/8-Inch Drill/Driver Review: Is This 12V Brushless Cordless Drill Worth Buying?

The Milwaukee M12 FUEL Subcompact Brushless 3/8-inch Drill/Driver, model 3401-20, is aimed at people who already live on the M12 battery platform—or who want a genuinely small cordless drill that still uses a brushless motor. Full product focus for this review: Milwaukee M12 Subcompact Brushless 3/8-inch Drill/Driver Model 3401-20 (tool-only style listing).

Below you will find an overview, key features, how it performs for everyday drilling and driving, verified-style specifications we can stand behind, what typically comes in a bare-tool box, pros and cons, who should buy it, a comparison against other-brand 12V-class drills, FAQs, and a final verdict—with a product-specific Amazon link so you can check current kit contents and pricing.

Overview

Subcompact 12V drills exist because full-size 18V/20V hammer drills are often more tool than you need for cabinetry, electrical boxes, furniture assembly, fixture installs, and work overhead or inside cabinets. The 3401-20 pairs Milwaukee’s M12 FUEL brushless approach with a 3/8-inch chuck in a short body meant for one-handed control and tight clearances.

If you already own M12 batteries for lights, multi-tools, or ratchets—see also our Milwaukee M12 FUEL cordless 3/8-inch high speed ratchet review—this drill is a natural add-on. If you are starting from zero batteries, budget for at least one M12 pack and charger, or look for a kit SKU on the product listing.

Key Features

• Milwaukee M12 FUEL subcompact brushless 3/8-inch drill/driver
• Model 3401-20 — commonly sold as tool only (confirm listing)
• POWERSTATE brushless motor
• 3/8-inch chuck for everyday bits
• Variable-speed trigger with two mechanical speed ranges
• Compatible with the Milwaukee M12 battery ecosystem
• Compact form factor for tight spaces and overhead work
• Built-in LED work light

Performance / How It Performs

In day-to-day use, expect the 3401-20 to feel like a modern compact brushless drill: smooth trigger ramp-up for starting holes cleanly, enough clutch control for driving screws without stripping soft material, and a short body that fits where a bulky 1/2-inch hammer drill will not. The 3/8-inch chuck is the right size for most household and light trade bits; it is not meant to replace a full-size 1/2-inch hammer drill for large hole saws or masonry anchors.

Runtime and peak feel still depend on the M12 pack you choose. Higher-capacity packs support longer sessions; compact packs keep the tool light for ladder work. For continuous high-volume fastening, many pros still pair a compact drill with a dedicated impact driver—see our Milwaukee M18 FUEL 1/4" hex impact driver review for that tool class—while keeping the 3401-20 for precision drilling and lighter driving.

Specifications

• Model: 3401-20
• Brand: Milwaukee
• Product: M12 FUEL Subcompact Brushless 3/8-inch Drill/Driver
• Chuck: 3/8 inch
• Motor: Brushless (POWERSTATE / FUEL)
• Function: Drill / driver (not a full-size hammer drill replacement)
• Power source: Milwaukee M12 cordless (battery not included on typical 3401-20 bare tool)
• Configuration: Tool only (verify current Amazon kit contents)
• Platform: Milwaukee M12

What Comes in the Box

• Milwaukee M12 FUEL subcompact brushless 3/8-inch drill/driver, model 3401-20 (tool-only configuration on many listings)
• Battery, charger, bits, and case are not assumed—always confirm the exact Amazon listing before purchase

Pros

• Genuine subcompact size for cabinets, electrical, and overhead work
• Brushless FUEL motor on the widely used M12 platform
• 3/8-inch chuck covers common household and light trade bits
• Tool-only path is efficient if you already own M12 batteries
• Strong fit for electricians, HVAC helpers, and finish carpenters who want less bulk

Cons

• Bare 3401-20 typically does not include a battery or charger
• 3/8-inch chuck and compact frame are not ideal for large hole saws or heavy masonry
• New Milwaukee users must budget for M12 packs and a charger
• Users standardized on DEWALT 20V MAX or Makita 18V may prefer staying on one charger ecosystem

Who Should Buy It

Buy the 3401-20 if you want a small brushless M12 drill for furniture, fixtures, electrical boxes, light carpentry, and maintenance work in tight spaces. It is especially sensible if M12 batteries already power your lights, multi-tools, or ratchets.

Who Should Consider Another Option

Choose a full-size 1/2-inch hammer drill/driver if you regularly drill masonry anchors or large holes. Skip a bare tool if you have no M12 batteries and want a complete kit in one box. If you are locked into another brand’s 12V or 18V/20V line, staying on that platform usually beats mixing chargers.

Why Buy It

The 3401-20 earns a place when size and M12 compatibility matter more than raw 18V bulk. You get a brushless subcompact 3/8-inch drill/driver that fits real cabinets and overhead work without forcing you onto a second battery system if you already run Milwaukee 12V tools.

Final Verdict

The Milwaukee M12 3401-20 subcompact brushless 3/8-inch drill/driver is worth buying if you need a small, efficient M12 drill and already own—or plan to build—an M12 kit. It is not a substitute for a full-size hammer drill, but for cabinets, electrical, and light trade work it is a smart, platform-friendly choice. Check current contents and pricing on Amazon before you buy.