How do you track annual investment gains vs contributions in your ISA?

People who have a stocks and shares ISA, how do you track your annual contributions, separate from investment gains?

At moment I’m just downloading the bi-yearly statements of total ISA portfolio value, whacking in a spreadsheet, and subtracting my monthyl contributions to get to the return on investment.

Is this right or is there a better way to do this?

Also do you keep track of calendar year returns, or over one tax year returns, or both?

Are there some useful apps or downloadable spreadsheet formats for this?

Cheers for any thoughts