Mortgaging versus renting

Some people have arguments about whether it's better financially to mortgage a place to live, or to rent one (either saving for a cash purchase later or just renting for life). The answer could depend on many future developments hard to predict, from the movement of financial markets to events like unemployment, hyperinflation, institutional collapse, wars and disasters, or government makeovers, and I can't write a program to calculate these. But for some quick "back of the envelope" figures, put your guesses into the simulator below and press the button. Use this at your own risk but I hope it helps settle arguments. The calculations are implemented as Javascript so programmers can see how they work and no figures are sent to my site.

Amount of money in your 'housing' account right now:
Additional funds (if any) that are to be used only for mortgage deposits (for example if the buyer's family wants to help and doesn't believe in anything else; do not count loans here)
Amount you think you can deposit each year:
inflating by	% p.a.
and stopping after	years
Your guess of the long-term savings interest rates (taking into account future changes):	% AER
Your guess of the long-term borrowing interest rates (again taking into account future changes):	% AER
Current cost of renting:	per
inflating by	% p.a.
Current cost of buying (including extras):
If you think it's in a 'bubble' or other anomaly, what is your guess of the current cost (including extras) if the anomaly weren't there? (leave blank if you don't think it's anomalous)
and what is your worst-case scenario guess of how long this anomaly could last?	years
Apart from this, what is the usual change you want to simulate?	by % p.a.
Any extra earnings (after tax) you hope to get per year if you plan to rent out a room after you buy (remember it might not be occupied all the time):
and your guess of how this might change:	by % p.a.
Extra cost per year to own a place, including maintenance, insurance, extra grounds tax, etc:
inflating by	% p.a.
Now press:	(or )
Strategy 1: Rent, save and buy with cash
Would it work?
after	years
Would it run out of money?
after	years
Strategy 2: Borrow to buy and pay off
Would it work?
after	years
Would it run out of money?
after	years
Strategy 3: Just rent
This housing account should last	years

All material © Silas S. Brown unless otherwise stated.
Javascript is a trademark of Oracle Corporation in the US.
Any other trademarks I mentioned without realising are trademarks of their respective holders.