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 2017by Hannah WalshWe review sat navs and apps from top brands such as Garmin, TomTom and Waze. Here's our pick of the top five sat navs for 2017FeaturedTop five Garmin sat navsby Hannah WalshGarmin is one of the top names for sat navs. Our experts pick out the best of the bunch of Garmin's sat navs.FeaturedTop five TomTom sat navsby Hannah WalshAlong with Garmin, TomTom is one of the most popular sat nav brands. Our experts pick out the best of the bunch of TomTom's sat navs.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 sat nav buying guide helps you cut through the jargon and find the best sat nav for your driving needs.Buying sat nav mapsLearn how to update sat nav maps with our expert guide, including where to get the maps, how to install them, and whether it's worth updating an old sat nav. How we test sat navsWe put every sat nav through our thorough tests, so you can avoid muffled audio instructions or being told to do a U-turn on a dual carriageway.Built-in sat navs explainedOur expert advice can help you decide if a built-in or in-car sat nav is right for you, or whether a standalone Garmin or TomTom sat nav is the best choice.Top 5 best sat nav apps for 2017We review sat nav apps from leading brands such as Garmin, TomTom and Waze. Our experts pick out the top five sat nav apps for 2017Top 5 best free sat nav apps for 2017We review sat nav apps from top brands such as Garmin, TomTom and Waze. Our experts pick out the top free sat nav apps from 2017Best cheap sat navs 2017The best cheap sat navs of 2017, including sat navs from TomTom and Garmin.Apple Maps vs Google MapsNot sure whether Apple Maps or Google Maps is best for you? See our guide on these popular sat nav apps.What is GPS?How does GPS work? Do you need to be connected to wi-fi for it to work? Do your sat nav, iPad, iPhone and Android smartphone use GPS?