Sat navs advice guidesSat nav or sat nav app? Garmin or TomTom? We've got expert advice on buying the best sat nav or sat nav app for you.FeaturedTop five sat navs for 2018by Hannah WalshGet clear and efficient navigation for every single journey with the top five sat navs for 2018. We've tested the latest portable models and sat nav apps from brands such as TomTom and Waze - discover the models we recommend.FeaturedTop five best Garmin sat navs for 2018by Hannah WalshGarmin is one of the biggest names in the sat nav business. Discover the Garmin sat navs that excelled in our independent tests, and whether they're a better choice for you over a rival TomTom device, in our expert guide. FeaturedTop five best TomTom sat navs for 2018by Hannah WalshAlong with Garmin, TomTom is one of the most popular sat nav brands. Our experts give their pick of its extensive model range, in our guide to the top five TomTom sat navs. Find out if you should choose one over a Garmin model.Put us to the testOur Test Labs compare features and prices on a range of products. Try Which? to unlock our reviews. You'll instantly be able to compare our test scores, so you can make sure you don't get stuck with a Don't Buy.Sign up nowor loginHow to buy the best sat navOur expert guide helps you choose the best sat nav for your driving needs by cutting through the jargon. Find out if you need a feature-laden, premium portable sat nav, or whether a smartphone sat nav app would be better value. Buying sat nav mapsKeep your sat nav up to date with the latest maps and software updates. Our expert guide will show you where to get maps for your device, how to install them, and whether upgrading to the latest maps is worth it on older devices.How we test sat navsHow we independently test the latest portable sat nav devices and apps to uncover Which? Best Buy sat navs. These offer the best audio and visual navigation quality so you aren't left circling a roundabout by ambiguous directions.Built-in sat navs explainedBuilt-in sat navs are offered on everything from luxury saloons to basic superminis, but are they worth the extra money over the best portable sat navs and apps? Our guide will help you choose which system is best for your needs.Top sat nav appsSat nav apps for your smartphone or tablet can offer navigation quality and features to rival some of the best dedicated sat navs. Our experts guide you through the top five sat nav apps for 2018 to help you choose wisely.Top free sat nav appsA free sat nav app needn't be a compromise compared to a full sat nav. Our experts pick the best top free sat nav apps for 2018, from big brands such as TomTom and Garmin, and popular traffic-busting options from Google and Waze.Top cheap sat navsChoosing a cheap sat nav doesn't mean you have to compromise on quality. Discover the top cheap sat navs for 2018, including the best TomTom and Garmin dedicated nav devices, as well as the best cheap and free navigation apps.Apple Maps vs Google MapsGoogle Maps and Apple Maps are the titans of the app navigation world, but which is best for you? Our guide reveals their key features, and whether it's Apple or Google that triumph in our rigorous in-depth sat nav testing.What is GPS?How does a GPS sat nav work? Find out about the technology behind your portable sat nav device or smartphone app, and whether you need additional connectivity such as wi-fi or Bluetooth for traffic and live-data services.10 essential Google Maps tips and tricksWe've rounded up some tips to turn you into a Google Maps power user, plus a few extras to put a smile on your face.TomTom vs Garmin sat navsCan't decide between a TomTom or Garmin sat nav? device Our expert guide explains the key features and differences between these two major navigation brands, to help you make the best choice for your driving requirements.Caravan and motorhome sat navs explainedCaravan and motorhome sat navs can solve some of the problems of exploring the great outdoors in these vehicles. Our guide explains the benefits of these sat navs, which let you tailor your route based on the size of your rig.How to use your sat nav legally and safelyFollow the Which? guide to staying safe and on the right side of the law when using your portable sat nav device or smartphone app, including where to place your sat nav and the rules on using your phone while driving.