Unfortunately, that's not an "easy" question to answer any longer.
If you were using what they used to call "Simple Interest", then it would be 4% each year.... so
$500 + 4% year 1 = $520
$520 + 4% year 2 = $540.80
$540.80 + 4% year 3 = $562.43
$562.43 + 4% year 4 = $584.92
$584.92 + 4% year 5= $608.32
$608.32 + 4% year 6 = $632.65
$632.65 + 4% year 7 = $657.96
However, if you use a compound interest calculator, then you would use this formula:
A = P(1+ r/n)^nt
Where P = Principal
r = Annual interest rate
n = number of times the interest is compounded per year
t = number of years
So.... $500 at 4% compounded daily would work to:
A = 500(1+.04/365)^365*7
A = 500(1+.04/365)^2555
A = 500(1.00010958904109589041095890410958904)^2555
A = 500(1.3231095139022953872398959866383)
A = 661.56
(Thanks to my wife the banker for verifying this for me)
5259.81
It will be worth 457.96
1136.23
556.34
730.43
5259.81
It will be worth 457.96
1136.23
It will be worth 417.72, approx.
523.97
635.61
661.56
332.01
543.66
556.34
730.43
762.73 - 762.75