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How we test sat navs

Sat navs: How we test sat navs

Which? test lab

Which? tests almost 3,000 products every year, including more home technology products than anyone else. We look at new products as soon as they are announced, helping you to understand new technologies, and whether they are worth your money.

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• Our tests are based on years of testing experience
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• We buy everything we lab-test
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Which? exists to give consumers impartial advice, which means that if a product isn't any good we'll say so, without fear of penalty. Which? works for you, providing trustworthy advice without a hidden agenda.

We examine everything that matters across all products, including performance, features and how well they work in real life – so you'll know exactly what to expect. Our unique, comparative lab tests mean you can trust our Best Buy and Don't Buy verdicts and choose with confidence.

Try Which? today for just £1 to find out which sat navs we rated as Best Buys.

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Sat nav testing in brief

Which? tests over 30 sat navs and sat nav apps a year to ensure that our guides only have the models that are currently available.

We test a range of sat navs covering dedicated devices (including those aimed at motorbikes) as well as mobile phone navigation apps to identify which are the best for coping with modern roads, which are the simplest to use and the most efficient at getting you to your destination.

We aim to ensure all the major brands are represented.

Testing updates

Due to improvements in our testing procedures to account for new features and developments, please note that scores of sat navs tested after February 2013, are not exactly comparable with those tested before.

How we choose products for testing

Dedicated Business Researchers carefully select the products Which? tests, scouring the market for the latest releases and the most innovative products. Our Business Researchers aim to cover a very high percentage of the market in any one product area. And, while we do test some premium products, we avoid testing those products which you would need a second mortgage to afford. We take the following criteria into account when choosing sat navs:

• Popularity – we test sat navs that are the biggest sellers
• Brand reliability – we test more sat navs from brands that are reliable and tend to do well in our testing
• Innovation – we test new and innovative sat navs
• Cost – we typically test sat navs that cost between £50 and £200, and apps from free to £70.

We examine each sat nav carefully and rate its features

Ease of use

Our expert assessors test our products for their ease of use by running through everyday scenarios that replicate how you use your sat nav.

We start assessing each sat nav right after pulling it out of the box, looking at the setup process, installing the latest updates and how easy it is to secure to your windscreen or dashboard.

We program in routes, change the route, save favourite routes and search for points of interest. The audio and on-screen instructions and map displays are also tested in depth to reveal which devices lead you to your destination in the clearest way without you ending up at a dead end.

Which? tests each sat nav system with a number of target locations, including some newly built addresses, looking at whether each sat nav can find the target, how logical the planned route is and how close to the target the sat nav system gets before saying it has arrived.

Road testing sat navs

Technical testing

Our products undergo an extensive range of objective laboratory and road testing to assess performance.

• The features and capabilities of a sat nav are explored in depth and we test whether you can select your destination from full postcodes, street names or favourite and previous destinations.

• We also look at the routing options so that you can take the scenic, most fuel efficient or fastest route to your destination, as well as the ability to avoid toll roads and motorways. The points of interest are also checked, and we also look at speed camera warnings and whether live traffic information is available.

• Each sat nav is subjected to our extremely demanding test route, which includes busy city streets, complex junctions involving several turns in quick succession, multiple lanes, and single and multiple lane roundabouts

• We check if the sat nav can guide you through complicated turns with multiple instructions, and whether it tells you which lane to be in. Where there might be two mini-roundabouts straight after each other, it's crucial the sat nav system can provide instructions in time for the driver to follow them – the best sat navs can do this. We test this at junctions and roundabouts in all areas, but it's of particular importance in busier inner-city streets where there may not be the time or opportunity to correct any wrong turns.

• We deliberately go off the pre-determined route to test how quickly each sat nav system recognises the diversion and recalculates the route, considering our new direction.

• Road tests are carried out with a driver and assessor. The same car is used each time to ensure consistency. Marks are awarded for accuracy of route mapping, quality and clarity of visual and audio instructions, accuracy of fine detail and more.

Ratings explained

All data sent back from our laboratories is carefully analysed by Which? staff so that the highs and lows of every product are revealed. If anything does not add up with a product then we will retest it. If there's a fault we'll purchase a new product to see whether it’s a one-off issue, or symptomatic of a larger problem. The sat nav score ignores price and is based on:

• Ease of use 50%
• Performance 25%
• Versatility & features 25%

Ratings system: