What is the double entry system?

The double entry system of accounting or bookkeeping means that every business transaction will involve two accounts (or more).

Every transaction has two effects. For example, if someone transacts a purchase of a drink from a local store, he pays cash to the shopkeeper and in return, he gets a bottle of dink. This simple transaction has two effects from the perspective of both, the buyer as well as the seller. The buyer's cash balance would decrease by the amount of the cost of purchase while on the other hand he will acquire a bottle of drink. Conversely, the seller will be one drink short though his cash balance would increase by the price of the drink.

Traditionally, the two effects of an accounting entry are known as Debit (Dr) and Credit (Cr). Accounting system is based on the principal that for every Debit entry, there will always be an equal Credit entry. This is known as the Duality Principal.

Debit entries are ones that account for the following effects:

    Increase in assets
    Increase in expense
    Decrease in liability
    Decrease in equity
    Decrease in income

Credit entries are ones that account for the following effects:

    Decrease in assets
    Decrease in expense
    Increase in liability
    Increase in equity
    Increase in income

Double Entry is recorded in a manner that the Accounting Equation is always in balance.

Assets - Liabilities = Capital

Any increase in expense (Dr) will be offset by a decrease in assets (Cr) or increase in liability or equity (Cr) and vice-versa.

Every transaction has two effects. For example, if someone transacts a purchase of a drink from a local store, he pays cash to the shopkeeper and in return, he gets a bottle of dink. This simple transaction has two effects from the perspective of both, the buyer as well as the seller. The buyer's cash balance would decrease by the amount of the cost of purchase while on the other hand he will acquire a bottle of drink. Conversely, the seller will be one drink short though his cash balance would increase by the price of the drink. - See more at: http://accounting-simplified.com/double-entry-accounting.html#sthash.xVKlQiR6.dpuf