Mortgage Repayment Calculations

Cruelemort

I am currently building a small widget that calculates exactly how much of your mortgage you have paid off on any given day (inc. how much interest you have paid and how much you have left to pay) but am trying to work out some of the mechanics of the calculations.

I understand how daily interest rate calculation mortgages work but am trying to figure out monthly and annually. With annual interest, if you take out a mortgage on, say, 1st Feb, will the mortgage company immediately calculate a years worth of interest and add that on from the first day, then on 1st Feb the next year calculate the years interest on the balance from that day and add it on, etc?

I am also trying to understand how first payments work. When I got my mortgage, I completed on 23rd of June, my first payment came out exactly 1 month after (23rd July) and from then on mortgage payments came out on my selected repayment date (so 3rd August and 3rd of every month after). Is this a standard thing that all mortgage companies do? If so, does this happen only for new mortgage or for remortgages as well?

The widget for if anybody is interested (http://www.howmuchhaveipaidoff.co.uk/)

ACG

I dont mean to P on your parade, but this might be useful for you - i use it occasionally when clients dont have a clue how much their mortgage balance is http://www.amortization-calc.com/

Cruelemort

Thanks for the response. The tool you linked to is similar in principle to what i am trying to build, although i am looking at including more complex variables and options. I did try to use it and it did not seem to work properly (more likely i am not using i correctly) - here i have put in a loan term of 25 years for 250k mortgage and it says it will be paid off in 3 years?

Any advice on my other questions?

Thanks

getmore4less

Daily is a bit too fine an increment as most mortgages these days are monthly.

even most daily interest compound monthly so there are only 2 changes in capital a month, payment made interest added and if these are the same day only one change in amount owing.

http://www.whatsthecost.com/mortgage.aspx

will get you close enough for most mortgages.

Thrugelmir

Daily seems rather OTT.

Easy enough to create on a spreadsheet though.

Daily interest is calculated and charged monthly. So you'll need to know the day of the month.

Then just factor in the date repayment hits your account.