The main factors in calculating insurance
The type of car you have
The value of the car is of course important, as the more expensive it is, the more it'll cost your insurers if you need to make a claim if your car is ever written off. Cars are also categorised into insurance groups, and that plays an important role in calculating your premium. Lastly, modifications can also affect insurance costs and you need to let your provider know about them.
Young people between 17 and 25 have a hard time when it comes to insuring a car – sometimes the insurance is as expensive as the vehicle itself. Thankfully it does settle down once you reach 26. There are ways of softening the blow, though. It might be worth considering a telematics policy.
Where you live
The insurers look at the crime rate, how busy the area is, and work out how likely it is that you will make a claim. More about this here.
What you do for a living tells the insurers more about you and how likely you are to claim. You may think, quite rightly so, that racing car drivers pay more for their car insurance. But you may be surprised to learn that some more common job types are also likely to pay more. This is due to a number of factors, including being seen to drive more.
Your driving history
This has a varying degree of impact depending on what you've got to declare. As you’d expect, three points on your licence for a minor speeding offence will not have as much of an effect on your premium as a previous ban for drink driving.
Anyone else who's on your policy
Everyone who is named on your policy will contribute to the premium calculation - so if you have a 19 year old teenager to add to your policy, or a partner with a previous driving conviction, you may want to think again whether you really want to add them to your policy, or at least make sure you’re sitting down when the quote comes through. More about this here.