Producer Surplus

An economic measure of the difference between the amount that a producer of a good receives and the minimum amount that he or she would be willing to accept for the good. The difference, or surplus amount, is the benefit that the producer receives for selling the good in the market.



This is shown graphically above as the area (Producer Surplus) above the producer's supply curve that it receives at the price point (P(i)). The size of this area increases as the price for the good increases. 

Investopedia explains 'Producer Surplus'

For example, say a producer is willing to sell 500 widgets at $5 a piece and consumers are willing to purchase these widgets for $8 per widget. If the producer sells all of the widgets to consumers for $8, it will receive $4,000. To calculate the producer surplus, you subtract the amount the producer received by the amount it was willing to accept, (in this case $2,500), and you find a producer surplus of $1,500 ($4,000 - $2,500).
Read more: http://www.investopedia.com/terms/p/producer_surplus.asp#ixzz2NAVznsvi
copy from  http://www.investopedia.com
to original website