Whether you choose, a fixed or variable interest rate is subjective to you and your circumstance.
A fixed rate ensures that your monthly payments will remain the same for an agreed period of time. For example, lenders usually agree to a fixed-term period between 2 to 5 years for buy-to-let mortgages.
Once this period has elapsed, your rate of interest will automatically switch to your lender's standard variable rate unless you agree to refix or change terms or even remortgage somewhere else. If you use us to buy your by to let or remortgage we will make a note in our diary to contact, you four months before your rate finishes to make sure you do not switch to the lenders variable rate which is normally a much higher rate than the rate you started on or the rate which you can switch to.
However, should you elect to take on a variable interest rate, you can expect your monthly payments to fluctuate and be much higher to start with.
Therein, if you have a tracker mortgage, your rate will follow the Bank of England base rate, whereas a variable rate mortgage has its interest rate determined by the lender and thus can change at any time.