Economic rent is not always the same thing as contract rent. A landlord may agree to let his tenant have the use of land for a smaller sum than competing renters would be willing to pay for the land in question. Here the sum actually paid, the contract rent, is not the economic rent. The economic rent is the competitive rent. Again, where there are buildings upon the land, the payment which the renter makes includes an element of interest. Here the economic rent is the difference between the contract rent and the interest on the improvements. Where the landlord uses his own land, we may say that the economic rent is the amount which would be paid for the use of the land if it were let under competitive conditions.