You see before you… (well, you’re reading on your screen, at least..) a lady most informed on the calculations of interest. You’d think that this would be easy to find, but Google wanted to point me to lots of calculators that would do it for me (but only based on a year) but nothing that would tell me HOW to figure it out myself.. But I finally found this very easy to read and understand tutorial of sorts. I highly recommend it.
So using my newfound knowledge, I set to work. I decided to run numbers just based on the 16k balance that will be on our citi amex card, which the 0% rate expires in October. The goal is to get it paid off by October. However, the balance won’t be 16k in April, it will be $13,250k, due to a big payment courtesy of my husband’s bonus.
Behold, the “just pay it down already!” scenario A:

So you know where those bigger numbers are coming from, $1300 is going to come from the regular debt snowball.
We will be receiving $1k back from our state taxes, and my husband gets an extra paycheck in april, so April’s numbers are 1300 + 1000+ 1800 = $4100.
In May, we’re expecting the tax stimulus check: 1300 + 1600 = $2900.
The rest of the months are “normal”.
Next, scenario B, let’s call it the, “Stuff it into savings instead” scenario:

Obviously, we will need to pay the minimum on the card, which I am going to say is $250. Now that I think about it, that’s probably high, but oh well. You can see the running balance for the card on the right, in yellow.
On the left in green, you can see the savings account. Each month, the month that would have gone to debt (minus $250), is instead put into savings. The bright green column is the interest earned for that month, with a tally of all the interest earned at the very bottom of that column ($189). The middle column is the running balance, adding the deposit as well as the interest from the previous month.
So when October comes, instead of making a deposit into the savings account, there will instead be a withdrawal of $10,700, and then that money, paired with the same $1050 debt payment we see in scenario A, is enough to pay off the amex balance in it’s entirety.
And the result? Instead of the 2k we started out with, we have $2189 - $189 in interest. Which we could then use to pay off our other debt.
THE RESULTS:
I’m nervous about my numbers. I calculated the interest using this formula:
.035 (our interest rate) x balance x 31/365 (a month’s worth of a year’s interest)
So if you take the initial $2000, it works out like this:
.035 x 2000 x .0849 = 5.94, or as my google doc spreadsheet rounded it off, $6.
If anyone wants to check and/or correct me, feel free (all THREE of my readers, haha!)
If the numbers are somewhat accurate… I am a little surprised. A benefit of almost $200 bucks in only 7 months is nothing to sniff at, in my opinion. This is looking like a decent scenario! Which makes me think I must have screwed something up somewhere! If I am … in the ballpark of accurate, then perhaps we shouldn’t even put the $2.5K from the bonus towards the debt this month - I could stuff it back into savings and transfer over a 16k balance to the 0% card instead of 13ishk and reap even better interest benefits.
This is definitely something to mull over. I’d welcome any thoughts and comments.