These two share a Darkfield sensor and the same three-device Easy-Switch count. The argument lives under your thumb.
The MX Master 4 puts haptic MagSpeed and an Actions Ring on a mouse you can order at $119.99 Amazon.com-sold. The MX Master 3S keeps a physical side wheel, and it is not a live buy on this page today.
So the fork is not cheap versus premium. It is whether the 4's thumb story is the mouse you want now, or whether you are waiting for a 3S wheel to come back.
This page is Graphite-class MX Master 4 versus MX Master 3S. Not the Lift. Not MX Vertical. Not a "best mouse" ranking.
Short version:
- Want the current MX Master you can actually buy, with haptic scroll and the Actions Ring: MX Master 4 at $119.99.
- Want a dedicated physical thumb wheel and you refuse the Actions Ring trade: wait for the 3S. It is not for sale here today.
- Already happy with a 3S on your desk: keep it. Identical Darkfield sensor and the same "up to 70 days" battery line do not justify a mid-life swap for vibes.
How they compare
| MX Master 4 | MX Master 3S | |
|---|---|---|
| Price | $119.99 (Amazon.com-sold) | Not a live buy today |
| Sensor | Darkfield, up to 8,000 DPI | Darkfield, up to 8,000 DPI |
| Scroll | Haptic MagSpeed | MagSpeed (no haptic) |
| Thumb control | Actions Ring (gestures) | Physical side scroll wheel |
| Programmable buttons | 8 (incl. Actions Ring) | 7 |
| Multi-device | 3 devices (Easy-Switch) | 3 devices (Easy-Switch) |
| Battery (published) | Up to 70 days | Up to 70 days |
| Weight | 150 g | 141 g |
| Surface (published) | Rubber-coated | Soft-touch plastic |
Same sensor. Same multi-device count. Same published battery ceiling. The argument lives in the scroll wheel and under your thumb.
Which job
Pick the thumb job before you romanticize a price that is not on the shelf.
The 4 adds haptic feedback on the MagSpeed wheel and swaps the side wheel for an Actions Ring you configure in Logi Options+. That is more flexible once you teach it your apps. It is also more homework than a wheel that just scrolls sideways on day one.
The 3S keeps the physical thumb wheel. Wide sheets, timelines, and canvases that want horizontal scroll without a gesture tutorial still prefer that. If you cannot buy a 3S today, that preference means waiting, not inventing a cart price.
If your day is browser, email, and short docs, the shared Darkfield sensor does most of the work on either body. The upgrade is not "more DPI." It is scroll feel and thumb layout.
The MX Master 4
Amazon.com-sold: $119.99.
Published line used here: Darkfield up to 8,000 DPI, haptic MagSpeed, Actions Ring, eight programmable controls counting that ring, Easy-Switch across three devices, up to 70 days on a charge, USB-C fast charge on Logitech's published "1 minute ≈ 3 hours" claim, 150 g, rubber-coated shell.
Buy the 4 because you want those controls now, not because a phantom 3S deal is "almost" as good. Almost only counts in horseshoes and marketing decks.
For palm versus handshake shape instead of 4 versus 3S, see MX Master 4 vs Lift.
The MX Master 3S
The 3S is not a live buy on this page today, so there is no cart price to quote.
When it is back, the published story that still matters is MagSpeed without haptic, a physical thumb wheel, seven programmable buttons, the same Darkfield ceiling, the same Easy-Switch count, up to 70 days, and 141 g on a soft-touch shell.
Until then, treat every "3S is the smarter buy at $X" sentence as a leftover from when you could actually check one out.
Which one to buy
There is no universal winner. Pick the thumb job.
- Take the MX Master 4 if you want haptic scroll and the Actions Ring on a mouse you can order today. Budget is $119.99.
- Wait on the MX Master 3S if the physical thumb wheel is non-negotiable and you will not relearn gestures for a ring.
- Keep a 3S you already like. Mid-life upgrades are how desks collect expensive paperweights.
- Vertical handshake instead: Lift vs MX Vertical. Wider field: /guides/best-wireless-mouse-productivity-comfort.
Frequently asked questions
Is the 3S still the "$30 cheaper" pick?
Not today. You cannot check one out here, so this page will not invent a cart price to keep an old headline alive.
Is the MX Master 4 worth upgrading from a 3S you already own?
Usually no. Same sensor family, same published battery ceiling, same three-device switching. Upgrade when your 3S dies or when you specifically want haptic scroll and the Actions Ring.
Does the 4 still have a physical thumb wheel?
No. The Actions Ring replaces that side wheel. If horizontal scroll without setup is the job, that is the 3S story when it returns.
Do both track on glass?
Both use Logitech's Darkfield sensor aimed at glass and hard surfaces. This page does not invent a thickness lab test beyond that manufacturer framing.
Is this a hands-on test?
No. Specs come from Logitech's published lines and the live Amazon.com-sold offer on the 4.
It is not a hands-on test of both mice. Amazon links are affiliate links. Paid placement is not accepted for coverage.