SEMrush.com
Formula:
Average Traffic % (PPC) value = monthly value
Example:
1000 total searches per month
If rank number 1 in Google will get around 400 searches per month
400 (Avergage Traffic %) x $12.00 (PPC Value) = $4800
You need to do this across multiple keywords
If you need to rank your customer for this keyword, you will get about 400 hits a month. If they want go to Adword and buy 400 hits per month for $12, they will need to pay $4800.
All the advertisers only get about 10% of the total clicks. If the volume is 1000 per months, then the most that customer will get is only 100 clicks per month.
So you may just charge 1/3 of the total cost that they will need to pay for Adword. Which mean they only need to pay you $1600 instead of $4800. Which mean they can save $3200 every month.
