Merits: 

1. Complete and Scientific: 

As it is based on definite principles and rules hence scientific. There is no chance of error because every transaction is entered twice. If any errors is left it is easily depicted. 

2. Basis of Account is Reliable: 

It is completely accountable as every entry is done twice in two books – once in Debit, other in Credit. 

3. It gives the information of profit and loss: 

Separate ledgers are made for every type of transaction. Hence, at any time businessman can get status of profit and loss of particular period. 

4. Easy in providing informations: 

As separate accounts are made for sale purchase, payment and received, and hence everything could be calculated easily. 

5. Less possibility of cheating and fraud: 

If any person does any fraud, he could be caught easily. 

6. Comparative study: 

At the end of financial year, final ledger is prepared which could be compared with the ledger of last year. 

7. Legal Authenticity: 

It is legally recognised by Company Act, bank, insurance, MNCs. Hence, all big companies are bound to keep their accounts act to this method.

Demerits: 

1. If any entry is left in journal, it could not be found. It would not affect balance sheet. 

2. If wrong amount is entered at initial stage, it would not be tally and there would be no effect on balance sheet. 

3. If any difference is entered in debit as well as credit side it would not be able to «. find if.

4. It is a costly method as many heavy registers have to be maintained. But such expenditure is negligible for big business houses compared to its utility. 

5. Specially trained and skilled people are required to maintain such records.