"Breaking" down fixed versus variable interest 
Sometimes you are also given the option of a fixed interest rate. With this option, the rate will not change, and is fixed for the duration of the loan (or, if the loan is longer than 5 years, then the fixed rate is usually fixed for a period of 5 years). With a fixed rate, even if the prime lending rate is increased or decreased, the repayment amount will remain unchanged.
Fixed Versus Variable Interest  Which Is Better?
So if you are presented with the option of a fixed rate or a variable rate, which one should you go for?I am putting the answer right near the top of the article, so that if anyone is looking for the short version, here it is:
It is pretty much always better to choose a variable interest rate instead of a fixed interest rate.
For those of you looking for the reasons behind why I say that, read on.
Interest Hurts The Most At The Start Of A Loan
The bottom line is this – at the beginning of a loan, only a small amount of the repayment value goes towards the principle debt. The rest of the payment goes towards interest. So it is in your interest (see what I did there?) to have a lower rate at the start of a loan rather than at the end of the loan.And this is where the problem with a fixed interest rate comes in…
The fixed interest rate you will get is almost always going to be higher than the variable interest rate you would get. One of the big cheeses over at Ooba, Kay Geldenhuys, explained it best in this article: "Banks hedge their own risk of the interest rate going up by only allowing the consumer to fix their repayments at a rate higher than the one they were paying before”
So a fixed rate means you will have a higher interest rate at the start of the loan – the part where it hurts the most!
Okay now I can hear you shouting the same reasoning the lenders use when presenting a fixed interest rate option:
“The fixed rate makes you secure in the knowledge that your monthly payment will not change. Even if interest rates rise, your monthly repayment amount will be unaffected”
And yes, this is true. But what they fail to tell you is that even if the interest rates did rise, even aggressively, it will take a few years for the value of the variable rate to increase and overtake the value fixed rate. By the time that happens, the damage caused by the higher fixed interest rate at the start of the loan is only partly offset by the gains of the lower fixed interest rate at the end of the loan.
That may sound complicated, so I think it is time for some examples…
Fixing Your Interest Rate In A Rising Interest Rate Environment
Consider someone taking out a R100k loan over 5 years (60 months). They get two options – a variable rate of prime + 0.5% (currently=10.75%) or a fixed rate of 12.75%.Let’s start off by loading the dice heavily in the favour of the fixed interest rate option. Let’s assume that the SARB jacks up the repo rate every 6 months by 0.5% for the duration of the loan. In other words the variable rate will move from 10.75% at the start of the loan all the way up to 15.25% by the time the last payment is made. (I.e. we are playing into the usual reason given for fixing your interest rate  that the interest rate can rise and you can end up on a higher interest rate).
The result of this scenario is summarised below:
Fixed Interest
(@ 12.75%)

Variable Interest
(Starts @ 10.75%, increases by 0.5% every 6 months,
until 15.25%)


Total Repaid

R135,751.80

R134,184.67

Total Interest

R35,751.80

R34,184.67

You can see that, even with the extremely aggressive increases in the prime lending rate, resulting in the variable interest rate ending up a full 2.5% higher than the fixed rate, the variable interest rate option still ends up costing around R1,500 less!
Let’s zoom in a little using some pictures...
First up let’s look at the monthly instalments for each scenario (click for larger image).
You will notice that, in the beginning, the instalments for the variable option are much lower than the fixed option (R2,137 versus R2,237). The variable interest rate instalments then get bumped up with each interest rate hike, until it overtakes the fixed interest rate repayments.
But visually, you can see how the big savings in instalments at the start of the loan are only partially offset by the additional costs at the end. Time to bring out my limited "Photoshopping" skills...
Or to put it another way, the next chart shows the interest paid per month for the variable and fixed interest rate loans (click for a larger image).
Again, you can see the damage done by the higher fixed interest rate at the start of the loan. The lower interest paid at the end of the loan is not enough to catch up!
So, in conclusion, even in a bit of a worst case scenario, the variable interest rate option comes out tops.
I just want to address one last counter argument in this scenario – the repayment amount at the end of the loan is higher for the variable interest rate option (R2,281.86) than for the fixed interest rate option (R2,262.53). This can cause someone to overspend on their budget, right?
Okay let me quickly smash this one out the park:
 If an extra R20 (or even R200 for that matter) a month on debt repayments is going to sink your budget – you are overextended and you should definitely not be taking the loan in the first place!
 By the time the variable interest instalment overtakes the fixed interest instalment, 3 years would have passed. In that time you should have received a few inflationrelated salary increases (heck if you were smart enough to choose the variable interest option, I would say you would have even got a promotion by then :P)
Fixing Your Interest Rate In A Flat Interest Rate Environment
Using the same parameters as the first example (a loan of R100k over 60 months with a fixed rate of 12.75% or a variable rate of prime +0.5 (=10.75%)) let's see what happens if the prime rate remains unchanged. I think the result is obvious (a loan at 12.75% is going to be way more nasty than a loan at 10.75%), but here are the actual numbers:
Fixed Interest
(12.75%)

Variable Interest
(Starts 10.75%, remains at 10.75%)


In a scenario where rates remain unchanged, you would have been R6,000 better off by going with a variable rate.
Fixing Your Interest Rate In A Falling Interest Rate Environment
Finally, let’s see what happens for that same loan if the prime interest rate decreased. Let’s say the variable interest rate starts at 10.75% and then the prime rate is decreased by 0.5% every year.
Fixed Interest
(12.75%)

Variable Interest
(Starts @ 10.75%, decreases by 0.5% every year,
until 8.75%)


You would have been over R7,900 better off by going with the variable rate! Win!
Time To Hit The Turbo
Here is something else to consider about the whole fixed versus
variable decision. If we consider our loan example, the two options were:
Fixed at 12.75% => Starting
Instalment R2,237
Variable at prime + 0.5% => Starting
instalment R2,137
The fact that you even considered the fixed option, means
that you could afford an instalment of R2,237. Yes?
But since you know that the
variable interest rate is the way to go, your instalment is now only R2,137.
Time to hit the turbo button on that loan – take the extra +R100
saving (you could afford the higher instalment remember?) and pump it back into
the loan. This will save you even more interest and reduce the loan term by a
few months.
Score again on the variable interest side!
So When Should You Fix Your Rate?
In the above examples, it was clear that going with the variable interest rate was the better option in a rising, flat and falling interest rate environment. So is there ever a time to fix your interest rate?
Always remember, the lenders are not in the business of screwing themselves over. If they are offering a fixed rate, you can be damn sure that the odds are weighted in their favour (and not yours). The bank is taking on some risk by fixing your rate, and you can be sure that they expect to be rewarded for sticking their neck out. Your fixed rate will always reflect this extra reward they expect.
Finally one last quote to put the final nail in the fixed interest rate coffin (found in this article)
"It is important to note that studies have found that over time, the borrower is likely to pay less interest overall with a variable rate loan versus a fixed rate loan."
Just go with the variable rate!
Till next time, Stay Stealthy!
 ~  ~