trucke said:
Let's throw some numbers out.
Option 1: Pay off mortgage faster and then save.
I'm using Duke's suggestion of $150k mortgage, 30 years, fixed at 4%. Payments are $716/mo. If we want to retire that in 20 years instead of 30, we need to add additional principle payment of $200/mo. So in 20 years mortgage is paid off. Mortgage interest payments total $67K. This saves $41K in mortgage interest charges.
Now we have the mortgage payment of $716/mo plus the additional $200/mo. This gives us a lot of options for our lives. However, using the original 30 year window, we now have 10 years to invest. Investment amount is now $916/mo. At 4% we can accumulate $134k in 10 years.
Option 2: Pay off mortgage in 30 years and save $200/mo.
Make regular mortgage payments. Save $200/mo for 30 years at 4%. This generates $137k in investment. So this is about $3k higher than paying off the mortgage faster. Mortgage interest payments total $108K.
You're comparing a guaranteed 4% return via early mortgage payoff to a potential 4% return via savings or investment. Obviously if the rate is the same, or even pretty close, then it makes sense to take the guaranteed return.
What others are saying, is that average stock market returns have historically been 7-8% over a 30 year period. So the choice is between guaranteed 4% payoff with the mortgage given in the example, and a potential return of quite a bit more than 4% via investment.
Here's the math using historical average returns of 7% for any money invested:
By paying 4% loan off early, you save $41k in interest. You then start investing the full amount previously applied to the mortgage and build up $158k over years 20-30 (assuming 7% return). So your total impact is 41k not spent on interest + 158k cash in an investment account = 199k net benefit via early payoff and then investing @ average returns.
If instead of putting that extra $200/mo into the mortgage you invested it into an index fund that was able to meet historical averages of 7%, you'd end up with $245k in investments after the same 30 year period. That's $46k more than the net benefit, and $87k more than the cash investment balance. That's a 19% increase in assets after 30 years (assuming money not spent in interest is the same as cash on hand, which may be a bit dubious). If you're just comparing the cash balances of each investment account, then paying off early leads to 34% less total assets after 30 years.
With current mortgage interest rates between 6-7%, (much closer to historical average returns) the guaranteed return of paying down the mortgage become more appealing. But for anybody that's got an interest rate below 5% they'll probably come out with a decent amount more money after 30 years by investing any extra money rather than putting it towards additional principal payments.