I want to compare the winnings from my premium bonds over the last 4.5 years with what I'd have got in interest if the capital had been in a savings account.
Basically I started with £x in bonds 4.5 years ago, I won 7 x £25 in prizes at random intervals and now have £Y in bonds (the winnings are reinvested automatically as more premium bonds).
I want to know what the equivalent in annual interest would have been if that capital and the prizes had gone into a savings account.
The complication is the random amounts and dates of the winnings and so I can't use any of the excel finance functions (as far as I know) because they assume regular payment periods and amounts. Bonds are drawn every month and I've only ever won £25 prizes so for practical purposes I've been making regular monthly payment of either £0 or £25 but with no pattern to which on which month.
I was thinking I might have to do it month by month but I wonder if there's a fancy bit of maths I can use? You guys never cease to surprise me with what you know so I thought I'd put it out there....
Thanks, guys.
Basically I started with £x in bonds 4.5 years ago, I won 7 x £25 in prizes at random intervals and now have £Y in bonds (the winnings are reinvested automatically as more premium bonds).
I want to know what the equivalent in annual interest would have been if that capital and the prizes had gone into a savings account.
The complication is the random amounts and dates of the winnings and so I can't use any of the excel finance functions (as far as I know) because they assume regular payment periods and amounts. Bonds are drawn every month and I've only ever won £25 prizes so for practical purposes I've been making regular monthly payment of either £0 or £25 but with no pattern to which on which month.
I was thinking I might have to do it month by month but I wonder if there's a fancy bit of maths I can use? You guys never cease to surprise me with what you know so I thought I'd put it out there....
Thanks, guys.
