And don't forget to subtract owner occupier mortgage interest tax relief (if applicable) from the gross interest figure to get your net interest (only) repayment.
Also - calculate the interest only repayment on the outstanding capital amount at the time you start paying interest only - and not the original amount borrowed.
Thanks so much posters.
serotoninsid, that is a brilliant calculator, it actually shows the interest only portion and the repayment.You would not believe how long I've searched for that!! Thanks
Karl Jeacle's calculator also shows the capital/interest split in case that helps. Not sure if it can model interest only periods on a mortgage - haven't checked...