Our Verdict

An honestly priced, rugged and reliable running watch. It's not glamorous, but then nor is slogging through sleet at 7am. The Polar M400 won't let you down, and the heart-strap bundle is a great all-round package.


  • Rock solid run tracking going cheap
  • Accurate heart-rate monitor
  • Decent value too


  • Separate HR strap may concern some
  • Unlikely to win beauty contests
  • Slow syncing

The Polar M400 GPS running watch is now eight months old, and with its separate heart-rate chest strap, could be seen as a little 'first generation' by wearers of new-fangled, non-runner-friendly Apple Watches.

However, don't be fooled - the Polar M400 is one of the best pure running watches around, especially for the money (under £100, under $150, around AU£200). Though I reviewed it with a bundled Polar H7 heart-rate strap, which pushes it to more like £150/$230/AU$320 at current prices.

Polar has considerable experience in the heart-rate tech market, and it brings its expertise to this relatively entry-point-priced product to lift it far above much of the competition. As with competitors such as the FitBit Surge and the Basis Peak, it's also got the activity tracking smarts of a simpler fitness band, so you get two in one, although arguably the value is mainly on the running side.

However, it's a holistic approach by Polar which can't really be carped at. As you can probably tell, I like this running watch.

Screen and battery life

Polar M400 on wrist

Design-wise we're are in a slightly retro, functional place, which is the only real negative about the Polar M400. The plus side of this is that the screen is big enough to see clearly what's occurring when one is charging about, something that physically smaller running watches struggle with.

It is monochrome dot-matrix style though, so nothing too smartwatch-esque (although a recent update has added notifications), but there is an excellent backlight, and the contrast is adequate in low-visibility situations like driving rain.

The back of the case is stainless steel, and contains a single micro-USB port with a tiny attached cover. The port covers off charging and PC or Mac syncing, via a standard, micro-USB phone charger - rather than some lumpy, proprietary nonsense. Hoorah!

Battery life without alert trickery is perfectly decent, with about eight hours of life with the GPS turned on, translating to a casual two-to-three of weeks-worth of regular training runs.

The simple, killer feature here, though is that charging is simplicity itself, thanks to the use of micro USB rather than complex cradles that you subsequently lose or break.

Strap, comfort, style

Look at the bokeh on that Polar M400 strap

The build quality of the Polar M400 running watch is excellent overall. The lightly rubberised strap in black or white has a not-unpleasant texture, and hasn't perished or hardened in regular use over several months.

There's a vast range of adjustment available in the traditional hole and buckle strap, and there's room for truly stick thin and the excessively brawny wrists alike. The buckle itself is stainless steel, so no allergy or durability issues, and is the double type, trapping the spare strap as well. A small retainer completes the job, and it's a good 'un - it stays firmly put in use, and due to the lack of inbuilt HR monitor you can wear it as tight or as loose as you fancy - you can even buckle it to a running bag or bike handlebars if you fancy.

The cover contributes to a claimed waterproofness to 30m. We've not taken it diving to test this to destruction yet, but in normal running use (sweat, showers, cleansing rinse under tap) there have been no issues. At 56.6g and 11.5mm thick the Polar M400 Running Watch isn't the chunkiest on the market, coming in around the middle of the range - it's easy to wear all day.