Comments on: Series I Bond Rate Calculator

By: Jeff

Jeff — Thu, 09 Jun 2011 16:24:42 +0000

Jim,
I don’t understand your formula. What if my interest is due semi-annually but the CPI index changes monthly. How would I calculate what interest I am supposed to get at the end of 6 months?
Thank you.
Jeff

By: Jim

Jim — Mon, 15 Jun 2009 19:18:39 +0000

You may have entered in the incorrect values into the calculator.

Your 3% and 2% figures are correct, but you must use the current inflation rate of -2.78%. That makes your current total rate on both bonds 0% (it’s negative but they can never return negative).

By: Jan

Jan — Mon, 15 Jun 2009 18:50:29 +0000

Jim,
I bought a 1000.00 I bond in 02/2001, and another in 03/2001. I am not getting what your calulator says. My rates for each are 8.40%; and my yeild is 6.32 and 6.30, respectively. According to your scale, my fixed interest is 3 and 2 per cent for may 1, 01 and Nov 1, 01. What did I do wrong? 3.568% is what I got using your formula.
Jan

By: Eric N.

Eric N. — Sun, 09 Nov 2008 03:00:52 +0000

You’re churning out calculators left and right aren’t you?