Income and expenses in USD

I am paid income in USD and I have expenses paid in USD. How am I allowed to calculate the conversion to GBP for both income and expenses? I have read you can use the spot price, monthly average or yearly average price. Can I choose which I use? Can I use a combination of these across different transactions as the monthly average me be higher than the spot for example. And can I choose to use my bank conversion rate paid when converting from GBP to USD and vice versa? Robert

Hi robert lea-kime,
You can choose any one of the 3 that fall within the tax year you are looking at or your bank conversion rate if that is more beneficial to you.
Thank you.