Milwaukee M18 FUEL 15mm vs Milwaukee M18 FUEL 21mm

Last updated: November 9, 2026

The Milwaukee M18 FUEL 21mm is the better dual action car polisher overall, rated 3.6 to 3.5. The Milwaukee M18 FUEL 21mm leads on correction. The Milwaukee M18 FUEL 15mm wins on features.

Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.

Milwaukee M18 FUEL 15mm vs Milwaukee M18 FUEL 21mm

Which should you buy?

Scores side by side

Each factor is scored 0-100 against the same fixed reference points for every cordless dual action car polisher; a clear win is highlighted. How we rank explains each one.

Factor weightMilwaukee M18 FUEL 21mmMilwaukee M18 FUEL 15mm
Overall rating3.6/53.5/5
Correction 30%100 21 mm orbit62 15 mm orbit
Value 25%48 $254.9948 $254
Warranty 15%50 3-year warranty50 3-year warranty
Power 10%50 18 V battery; cordless makers publish no motor rating (neutral score used)50 18 V battery; cordless makers publish no motor rating (neutral score used)
Weight 10%50 weight not published (neutral score used)71 5.2 lb
Features 10%15 cordless or a 20 ft+ cord60 constant-speed electronics, cordless or a 20 ft+ cord, lock-on trigger

Specifications

Milwaukee M18 FUEL 21mmMilwaukee M18 FUEL 15mm
Polishing
Orbit diameter21 mm15 mm
Speed range2,400-4,500 OPM2,650-5,100 OPM
Backing plate6 in5 in
Forced rotationNoNo
Power
Power sourceCordlessCordless
Battery18 V18 V
CordCordlessCordless
Brushless motorNot listedNot listed
Controls
Constant-speed electronicsNot listedYes
Soft startNot listedNot listed
Lock-on triggerNot listedYes
Build
Weight-5.2 lb
Pads or polish includedNoNo
Warranty3 years3 years

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