Samsung Galaxy Watch 9 40mm Battery Boost Explained

The battery grows to 390mAh at 40mm and 445mAh at 44mm

Galaxy Watch 9 ships with a 390mAh battery in the 40mm size and 445mAh in the 44mm, both bigger than Galaxy Watch 8's 325mAh and 435mAh.

1 min read

Samsung Galaxy Watch 9 Guide

Samsung Galaxy Watch 9

2 generations

How we know this

What changed, newest first.

OutcomeRightIt turned out as reported.

Jul 14, 20269to5Google

Disputed

Lists 325mAh for 40mm, not 390mAh, while retaining 445mAh for 44mm Read 9to5Google

+1 outlet

Jul 10, 2026WinFutureInternal documentRaises the 40mm battery to 390mAh+1 outlet

May 11, 2026SammyGuru+1 outlet

Reported

Frequently asked

Is the 40mm battery bigger?

Yes. Samsung confirmed 390mAh for the 40mm, up from 325mAh, and 445mAh for the 44mm, up from 435mAh.

Does a bigger battery mean longer life?

Not on its own. Battery life also depends on the chip and the software.

Latest Samsung Galaxy Watch 9 news