Apple Watch Series 4 40mm vs 44mm: What size Apple Watch should you get?

Make no mistake, both versions of the Apple Watch Series 4, 40mm and 44mm, are identical except for the display size. Features remain the same.

Time to compare

Unlike traditional watches, which measure case size horizontally, Apple measures the Apple Watch vertically. The smaller of the two Series 4 watch sizes has a height of 40mm; the larger, 44mm. When it comes to width, the smaller Apple Watch is 34mm wide; the larger, 38mm.

	44mm	40mm
Display area	977 sq mm	759 sq mm
Display size	448x368 pixels	394x324 pixels
Official Apple band exclusives	4	3
Entry-level GPS	$399	$429
Entry-level Cellular	$429	$529

The size differences of the two Apple Watch Series 4 models might not sound like very much — 3-4mm here or there — but 4mm out of 40mm is one tenth of the Apple Watch's dimensions.

The rounded rectangular shape of the Apple Watch makes it hard to compare directly with your average round watch, but in the traditional watch world, neither of the Apple Watches would be considered overly wide or high. Big watches are typically closer to 45mm wide.

Even if you think you want to go small, you can still consider both sizes — neither is enormous — though those with smaller wrists may find the 40mm fits more comfortably on the wrist.

The watch's different case sizes also translate to different display sizes. Both are Retina-quality, which means the pixels are invisible to the naked eye at normal viewing distance. The bigger Apple Watch simply has more of those pixels:

The 40mm Apple Watch has a display size of 394x324 pixels The 44mm Apple Watch has a display size of 448x368 pixels Again, this year's small watch has a slightly bigger display than last year's big watch. Let that sink in.

watchOS will fill whatever size display you choose, and for many people, it won't make any difference; that said, if you want more pixels, which translates into bigger text and images, it's worth considering.

Depth perception

Unlike the Watch's two height options and two display densities, there's no difference when it comes to the thickness (or thinness) of the two sizes.

That's because, unlike traditional mechanical or digital watches, the Apple Watch case has to hold a Retina display, the system-in-a-package (chipset), battery, and sensors. If you're trying to figure out which Apple Watch will best fit under the tight cuffs of your shirt, they're both about the same.

Hers and his

Because there are two sizes, and because some of Apple's bands are unique to one size or another, some have tried to simplify the size discussion down to "hers" and "his."

People come in all shapes and sizes, though, and so do tastes. Some women will want the bigger Apple Watch, and some men, the smaller. Some people with small wrists will want the bigger watch, and vice versa.

All this to say — get the size you prefer. Try both on, and see which one better fits your wrist, style, and personality. That's why Apple has sizes, after all, and why both sizes come with identical features.

Band Bias

Since Apple only offers some bands in some sizes, if you have your heart set on a certain band, you may have to be willing to go with the size that matches it. That said, you can get 3rd-party knockoffs for everything in every size and then some, so it only really matters if you want the real thing.

40mm-specific bands:

• Modern Buckle
• Hermès Single Tour (certain colors)
• Hermès Double Tour

44mm-specific bands:

• Leather Loop
• Hermès Single Tour (certain colors)
• Single Tour Rallye
• Hermès Single Tour Deployment Buckle

Battery life

The 44mm Apple Watch has a slightly bigger battery than the 40mm watch due to more room in the casing. If battery life is most important to you, this is something to take into consideration.