Forum Moderators: phranque
Your income can be looked upon as an annuity, so here's a handy calculator that figures out what an periodic income over a certain amount of periods is worth today.
http*://www.investopedia.com/calculators/AnnuityPV.aspx
1. For Interest rate, just type in 4% (which is the inflation rate),
2. for Number of time periods: if you didn't sell the site, how long would you be running it and making money off of it? (You can put in # of months or years or whatever, as long as the income you provide is for the same periods).
3. for the 'Payment Amount', type in your income per period (whatever period you used in step 2, i.e. if you used number of years, it would be the annual income) that you receive from the site.
Hit calculate. You will get a present value for your future income. The only way it's a good deal for you to sell is if the price is greater than this value.
Of course, this doesn't account for the risk of losing your business somewhere down the line, but if the risk is high, you can compensate by adjusting (eyeballing) the payment amount (down) or the periods (down) or a combo of both.
Hope that helps. Hey, Corporate Finance did come in handy after all :) yay for business school.