NS&I Green Savings Bond

BooJewels

LightKnow said:

^ I used interest calculator on this site but it wouldn't let me leave out how much you put away a month. So so added 1p 

Sounds like you used a regular saver calculator, if you had to add a monthly deposit to it.

To work out the interest over 3 years, the quick and dirty method is to work out the interest for a year, add that to the principle (amount you put in) in the account, work out the interest for the second year on the principle plus the 1 year of interest that was added etc.  Thus:

Year 1:  £3,000 @ 5.7% (3,000 x 0.057) = £171 = £3,171
Year 2:  £3,171 @ 5.7% (3,171 x 0.057) = £180.75 = £3,351.75
Year 3:  £3,351.75 @ 5.7% (3,351.75 x 0.057) = £191.05 = £3,542.80  

So your interest compounded over 3 years would be £542.80.  NS&I also publish that each £1,000 saved will be worth £1,180.93 after three years - which multiplied by 3 is indeed £542.80 of interest.  The published details on all saving accounts tends to show you what £1,000 would be worth at the end of the term, so you just need to multiply that by how many thousands you want to save.

refluxer

Yes, I think the calculators on the MSE site are for people who want to save on a regular basis and therefore aren't really geared towards this kind of 'lump sum' calculation.

@LightKnow - in addition to the calculation @BooJewels mentioned above, as interest is paid into this account (and therefore allowed to compound), you can also do another small calculation to work out the average return each year over the fixed rate period, if you're interested... 

£542.80 total interest / £3,000 initial lump sum = 0.1809, so 18.09% total growth
18.09% / 3 = an average return of 6.03% PA over those 3 years. 

LightKnow

I seriously like this forum, Thank you to the above users. ( Didn't think it be that straight forward to calculate)