Yes, more or less, if you're around an average user and don't have a lot of debt or credit and aren't coming off a very cheap fix.
Of course, if you're on an existing fix that carries on for a bit longer, your bill will stay the same, before the £400, but if you've fixed at a higher rate, it's worth checking what will happen to you. I think anyone who has fixed at a higher rate will be automatically moved to the new 2 year price cap, but I'm not certain about this.
If you're a low user, you might get away with a smaller increase because the £400 is a bigger proportion of your bill, but if you use above the average amount used to calculate the price cap, your bill will more than double as it's a smaller proportion.
All the above based on you using the same amount as last year, which may also change, as we could have a colder winter than the last few mild ones, or many people are going to actively reduce their consumption, to try and mitigate the price rises.
So given all the 'it depends' going on there, how can anyone take a statement like 'the maximum an average family can pay for fuel bills is £2500' at face value?