Mortgage question

[m0therofdragons]

We've been on the base rate for 2 years and pay the same each month on 2.5 per cent but as we're paying it off does the monthly payment ever change (clearly it would if the base rate went up but what if it stays the same? ).

Basically I've been looking at fixed rates but once you add in the fees we seem better off as we are even if it did go up but the thing I don't get at all is the calculator says that the percentage we're paying plus the amount we have left to pay means payments should be about £590 yet we're paying £620. We've been paying the same every month for more than 2 years but if it's based on what's left to pay shouldn't the monthly payments match the calculator?
How can I even check my bank is charging a certain %?

Your current payment is based on what was caculated when you took out the loan - so the total amount then. This is broken down over X number of monthly payments and then interest added daily or monthly (ours is about £10 a day) if you remortgaged now then your initial borrowing is less, as you've paid some off the capital. Hence the repayments being lower. Hope that makes sense.

Thank you