The missing pieces to this puzzle -
- Do you have any higher interest debt? If so, pay it first.
- Does your company have matching retirement funds (I'm thinking 401(k) but you have not tagged 'US')? Deposit at least to the match before prepaying any other debt.
- You set with other savings? Emergency fund, any other irregular expenses, etc.
- Is the rate on the mortgage an acceptable return?
The last point is this - paying one's mortgage early is "investing at the rate of the mortgage, fixed, guaranteed." So, my decision to pay off my 3.5% loan is nearly the same as to invest in a 3.5% CD. (Except the liquidity is a bit different, you send the bank an extra $1000, you're not getting it back. Not until you sell the house, of course.)
The postscript - the ratio of interest to principal is meaningless. At the beginning of a loan it will be a much larger ratio of interest to principal, at 4%, about 70% of the payment is interest on a 30 year amortization. Some innumerate folk will say 700(interest)/$300(principal) = 233% rate. This is nonsense, it's just the nature of paying the loan off. After the priorities above, pay more if you wish.