What's The Cost?
How much are you prepared to pay in interest?

The book Geek Logik by Garth Sundem attempts to break down a number of every day decisions into mathematical equations. It's an interesting read, and as I like numbers, I thought I'd include his "Should I buy it" equation here. I take no credit for the actual equation, but hopefully this calculator will help you make a purchase desicion!

Here is what infomation we need to work out this equation:
 WIN [ M(S - B - R) + £b ] = B  70 £i

WHow much do you want this thing?
NHow much do you need it?
IIs it a good investment?
MHow long have you wanted it?
months
(S - B - R)How much money do you have left at the end of each month?
(Note that I've combined this from (S - B - R), which originally was (Salary - Bills - Rent)
£ (Enter a negative figure if you always run out of money!)
£bWhat is your current net worth in bank and credit cards?
£ (Enter a negative figure if you're in debt)
£iHow much is the thing you want to buy?
£

Debt consolidation? No thanks! Become debt free by managing your own finances!