# Tissot PRX sizes: 35 mm and 40 mm on the wrist

Source: https://lumeandbezel.com/blog/tissot-prx-sizes
Published: 2026-10-09
Publisher: Lume & Bezel

**Short answer:** Tissot lists the PRX automatic in 35 mm and 40 mm cases, both 10.93 mm thick according to the listings. Because the bracelet flows straight out of the case with no lugs, the PRX wears larger than its diameter suggests. Many people with wrists under about 6.5 inches find the 35 mm easier to wear, while the 40 mm suits average and larger wrists.

The Tissot PRX is one of the most searched watches in its price range, and the most common question is which size to buy. The answer is not as simple as comparing diameters, because the PRX has an integrated bracelet that changes how big it looks and feels. This page is for buyers choosing between the PRX sizes online, especially if you cannot try one on first. It covers the listed dimensions, how the integrated design affects fit, how to match a size to your wrist, and what to know about the quartz and Powermatic 80 versions.

## The PRX sizes Tissot lists

In the Amazon listings we track, the PRX comes in two main case sizes. Both share the same 1978 style tonneau case inside a round bezel, and both are listed as water resistant to 10 bar (100 m). Tissot adds dial colors and versions over time, so if you see another size quoted, check the exact reference on Tissot's own site before ordering.

The 35 mm is sold as Powermatic 80 automatic and as Swiss quartz. The 40 mm is sold as Swiss automatic with the Powermatic 80 movement. Tissot quotes up to 80 hours of power reserve for Powermatic 80, which is why the movement is popular with people who rotate several watches. For more on the movement, see [what is Tissot Powermatic 80](https://lumeandbezel.com/blog/what-is-tissot-powermatic-80).

| Version | Case size | Thickness | Water resistance |
| --- | --- | --- | --- |
| PRX Powermatic 80, 40 mm | 40 mm | 10.93 mm | 10 bar (100 m) |
| PRX Powermatic 80, 35 mm | 35 mm | 10.93 mm | 10 bar (100 m) |
| PRX quartz, 35 mm | 35 mm | Check reference | Check reference |

Tissot PRX sizes from listings

Note: Listings give a single thickness figure for both automatic sizes. If thickness matters to you, confirm the current reference on Tissot's site, since figures can differ between versions.

## Why the PRX wears larger than its diameter

Most watches have lugs and a separate strap. On the PRX, the bracelet's first links are shaped to flow directly out of the case, so the case and bracelet read as one continuous shape. There is no visual break where a lug ends and a strap begins. Your eye takes in a wider, longer block of steel, and the watch looks bigger than a 40 mm round watch with traditional lugs.

The first bracelet links are also fairly rigid where they meet the case. That makes the effective lug to lug longer than the case itself, so the watch needs a little more flat wrist to sit well. The flat, polished bezel and the large dial opening add to the effect. The result is that a 35 mm PRX often looks closer to a typical 37 to 38 mm round watch, and the 40 mm can look like a 42 mm watch on some wrists. This is a common observation rather than a measured rule, so treat it as a guide.

If you want to understand the fit concept in more depth, read [lug to lug explained](https://lumeandbezel.com/blog/lug-to-lug-explained).

## Which PRX size fits your wrist

Measure your wrist with a soft tape just above the wrist bone. Then use these common guidelines as a starting point, and remember that thickness, wrist shape and taste all matter.

- Under about 6.25 inches: the 35 mm is the usual choice. The 40 mm is likely to reach the edges of the wrist.
- About 6.25 to 6.75 inches: either can work. The 35 mm looks classic and vintage sized; the 40 mm looks bold and sporty. This is the range where trying one on helps most.
- About 6.75 to 7.5 inches: the 40 mm is the common pick. The 35 mm can look small but some people prefer that look.
- Over 7.5 inches: the 40 mm, and possibly larger chronograph versions if Tissot offers one in the style you like.

[Try your numbers in the wrist fit calculator](https://lumeandbezel.com/tools/wrist-fit-calculator)

## Sizing the bracelet

A good bracelet fit matters more than usual on an integrated design, because you cannot swap to a soft strap to hide a poor fit. The PRX bracelet uses a butterfly clasp with push buttons, according to the listing. Fold clasps like this have no micro adjustment holes on many versions, so sizing comes down to removing links.

Size it so you can slide one finger under the bracelet on the underside of your wrist. Too tight and the rigid first links press into the sides of your wrist; too loose and the heavy head slides around. Many people find the watch fits best a little looser in summer when wrists swell. Our [bracelet sizing guide](https://lumeandbezel.com/blog/how-to-size-a-watch-bracelet) walks through removing links and keeping the clasp centered.

Note: If you plan to remove links yourself, use the correct pin pusher and work on a soft cloth. Many jewelers and Tissot dealers will size the bracelet for a small fee or free at purchase.

## Quartz vs Powermatic 80 in the same size

In 35 mm, you can choose quartz or automatic. The quartz costs less in the listings and runs from a battery, so it keeps time well and does not need winding. The Powermatic 80 automatic winds itself as you wear it, offers a long power reserve, and has the smooth seconds sweep that many buyers want from a mechanical watch. Size and look are close, so the choice comes down to budget and whether you want a mechanical movement.

We compare the two in detail in [Tissot PRX quartz vs Powermatic 80](https://lumeandbezel.com/blog/tissot-prx-quartz-vs-powermatic-80). If you are still deciding whether the PRX is right at all, see [is the Tissot PRX worth it](https://lumeandbezel.com/blog/is-the-tissot-prx-worth-it), or browse our [best Tissot automatic watches](https://lumeandbezel.com/best/best-tissot-automatic-watches).

## Water resistance and daily wear

Every PRX listing we track quotes 10 bar (100 m). Tissot's own wording in the listing says this is suitable for short periods of recreational swimming and showering, but no diving or snorkeling. That is more conservative than general 100 m guidance, so follow Tissot's wording for this watch. Details are in [is the Tissot PRX waterproof](https://lumeandbezel.com/blog/is-the-tissot-prx-waterproof).

Because the case and bracelet are mostly polished and brushed steel with sharp edges, the PRX shows desk scratches over time on the bracelet and clasp. That is normal for any steel bracelet watch and can be refinished at service.

## Frequently asked questions

**Is the Tissot PRX 40 mm too big?** For many wrists under about 6.5 inches it can look large because of the integrated bracelet. On average and larger wrists it usually fits well. Compare its effective length to the flat top of your wrist before deciding.

**Is the PRX 35 mm only for women?** No. Tissot labels some 35 mm listings as unisex. Smaller watches were the norm for men for decades, and many people with smaller wrists choose the 35 mm.

**Is there a 38 mm Tissot PRX?** The listings we track show 35 mm and 40 mm for the automatic. Tissot updates the range, so check its site for current sizes. Because of the integrated bracelet, the 35 mm often looks closer to a 38 mm round watch on the wrist.

**Can I put a strap on the PRX?** Tissot sells PRX specific straps that fit the integrated case shape. A normal straight strap will not fit the case properly.

## Gear guides for this topic

- https://lumeandbezel.com/best/best-tissot-automatic-watches
- https://lumeandbezel.com/best/best-swiss-automatic-watches-under-1000
- https://lumeandbezel.com/best/best-automatic-watches-for-small-wrists