Similarly, some mortgages have various terms.

Example, interest-only mortgages, where the mortgage is calculated over 30y, but pay only interest over 10y and then have a balloon payment after the 10y. Common in construction loans.

This would be so useful in Australia were interest rates for home loans are like Canada (mentioned above).

From discussion on Discord:

Having multiple loans that make up a mortgage would be a requirement. For example, if I buy a house using multiple loans (80% mortgage, 20% secured loan, etc).

Antoine’s comment would be useful. I’ve resorted to creating multiple debts to reflect multiple mortgage tracks/loans, each with different terms, time periods, amounts, payments etc.

I would also like to be able to run Monte Carlo simulations on different historical mortgage rates, to model a future purchase or refi. Should that be a different suggestion?

Absolutely.

This would be great or even just an option to refinance at x date and so forth

In the UK, and here is the scenario I have right now:

• We bought our current house and sold our previous last year. At the time of purchase, we were on a 2 year fixed rate mortgage, with a significant penalty to repay early (before the 2 years was up).
• We were able to roll this mortgage over to the new property, to avoid the penalty. So at the time of purchase, about 60% of the purchase mortgage was on this previous fixed rate which had about 6 months left on it, and the rest we fixed at a different rate for 5 years from the date of purchase
• When the 2 year fixed portion expired, we refinanced that onto a new 5 year fixed rate, which is a different rate than the other 5 year portion. So now we have two staggered fixed rates, one finishing about 6 months before the other in 2027
• Next year we plan to do some additional borrowing to cover the cost of some house work. This will likely be at a 2 year fixed rate
• In the next few years we’ll keep an eye on rates here (not looking good!) and either refinance everything onto a single rate in 2027, or keep staggering things to optimize the rates we’re on

This type of arrangement is not uncommon here in the UK, but is currently difficult to model in the tool!

Adding a +1 request for this one. Trying to model interest only repayments for investment property purposes in Australia

+1 to this

Even the most basic implementation of this would help, where you could specify for example a specific interest rate applying from year 0-X and X-Y.

Also helpful would be an “interest tax deductible” option, which would add any interest payable to your tax credits.

In Canada, fixed-rate mortgages (the majority of people have these I think, for a set term, usually 1-5 years) are compounded on a “semi-annual basis” - twice per year - this Option would be a nice and very easy addition to the compounding drop down, “Semi-Annual (Canadian Fixed Mortgages)”. Variable mortgages are less common here in Canada but they are compounded monthly. :)

Quick workaround to compounding differences for semi-annual for Canadian fixed is to calc and just adjust the interest rate to the equivalent monthly compounding rate. Close enough.

Another vote for the refi use case.

This would be great. Being able to model (1) a refinance and/or (2) an Adjustable Rate Mortgage.