I have been paying into a tax free index tracking account for a number of years, the amounts were only occasionally regular and varying in size. I haven't withdrawn anything.
I have exported data from the provider's website, so I know how much I have paid in over the years, and the date of each transaction.
The current value is a healthy amount higher than my contributions so I know it has grown, but is there any way to get an average interest rate or something, so I can compare my current price and transaction log with hypothetical performance if I had paid the same amounts on the same dates into fixed rate account?
There are countless calculators online that take a lump sum value and/or a monthly amount and an interest rate and spit out an answer, but I can't find anything capable of proving whether I would have been better or worse off with a safer account that won't fall with the markets.