How do i work out my bmr?

Calculate: You can get an estimate by using the following calculation. BMR = (height in centimeters x 6.25) + (weight in kilograms x 9.99) - (age x 4.92) - 161. The result will be in calories. Your true BMR will likely be different as it varies from person to person. The only way to do this that I'm aware of is using some pretty fancy laboratory techniques...

Formula here:: BMR = (height in centimeters x 6.25) + (weight in kilograms x 9.99) - (age x 4.92) - 161 However - some authorities would recommend adjustment for activity levels etc. If can afford it/available I'd suggest taking the estimate that you get from this and discussion with a dietician or personal trainer/exercise professional as is only a very rough guide to your specific needs