Click to view attachment As requested:

Here's the historic interest rates: http://213.225.136.206/statistics/rates/baserate.pdf

In the attached spreadsheet you can work out the average interest rates over any time frame, this also takes into account the duration of that rate, so a long period of no changes is taken into account:

Have a play around..:

Click to view attachment

Cheers = makes good viewing

Ok, updated the spreadsheet to include rates all the way back to 1922 (see attachment in header). Also has some inflation figures.

Thanks to Charlie the Tramp for adding in additional information!

Just some clarification, in the second column is the inflation rate for that year. As an example if the suffix M says 12 that means that £1 that year is equivalent to £12 today.

Here is the excel file with IRs back to 1694 and inflation inserted back to 1750.

Ok, updated attachment. Added simple average for comparison.

A most useful data set. Thank you for sharing it.

A question: I have been trying to work out the cumulative compounded interest since mid-1935, using the time period applying to each rate change. Do you have any ideas as to how I could do this, please?

That would be quite easy to do, just add your figure in down near the year 1935, and copy the formula up multiplying it against the interest rate divided by 365 for the daily interest rate (or if your smart work out how many days in that year, which will take into account leap years) times the number of days that rate was applicable.

Thanks, Jason. I will do that.

Jason have you updated the file to include the last rate hike ?

Done!

A further favour could you update the file in post #4. I tried on my download but am not familiar with playing with excel as I have a very old version.

Updated, but merged with the original document and inserted in first post. Couldn't attach to your post for some reason.

Is a further update now required Jason to take in the latest hikes ?

Done.

Hopefully, I'll have to update it again on Thursday.

Thanks Jason I will now be able to email it to my Clientele who have been pushing me for a few weeks. You would be surprised who is interested in this file.

Updated for the latest rate adjustment.

Interest rates reduced to 5.25% on 7th Feb 08. Attachment on first post updated.

Thanks Jason.