The difference in letout and rent is as follow;-

rent out means giving own property  to someone for use in consideration of money or something money value and let out means giving  property or something to someone for use in considerration of money or money value, of which we have legal possession not ownership.

the basic difference is only of "Ownership"

if there is any mistake plz make me inform so hat i can understand it betterly. 

Rentout : - If you rent something, you regularly pay its owner a sum of money in order to be able to have it and use it yourself.  

Letout : - In case of property It means the

property is leased/rented to the interested party on a monthly (or agreed) basis.

The difference lies in the two terms - Rent and Let as in both the phrases "Out" is common. 

.

We know that who gets "out" when the property is being let out or rented out.

.

The analysis given by Zeeshan Alam on the basis of "ownership" may be accepted upto some extent.  

.

However, in common parlance we use the phrase "let out " for own property also.  

.

P r a c t i c a l l y,

the difference can be found by property giving on rental basis or letting it out. If you receive the same amount in both the cases then there is no difference. Otherwise, Subtract (1) from (2) to get the difference..