The golden rule

The golden rule for converting a credit/debit accounting model to a source/destination model is:
  • Credit becomes Destination
  • Debit becomes Source

Impact on the balance sheet

Now let’s apply the golden rule to the balance sheet: Assets=Liabilities+EquityAssets = Liabilities + Equity

Assets

Assets are also called debit normal accounts. They are increased by debits and decreased by credits. Therefore, in the source/destination model, when an asset account is increased, the source component is increased, hence the balance is decreased, as per the balance equation: Balance=DestinationSourceBalance = Destination - Source.

Liabilities and Equity

Liabilities and equity are also called credit normal accounts. They are increased by credits and decreased by debits. Therefore, in the source/destination model, when a liability account is increased, the destination component is increased, hence the balance is increased, as per the balance equation: Balance=DestinationSourceBalance = Destination - Source.

Conversion example

Now, let’s convert common transactions from the credit/debit model to the source/destination model.

Topping-up a wallet with a bank transfer

Let’s consider a user topping-up their wallet with a bank transfer. To the business, the user wallet is a liability, and the bank account is an asset. In the credit/debit model, the transaction would be:
AccountDebitCredit
User Wallet$0$100
Bank Account$100$0
By applying the golden rule, we get:
AccountSourceDestination
User Wallet$0$100
Bank Account$100$0
From this, we can derive the balance of the accounts:
AccountSourceDestinationBalance
User Wallet$0$100$100
Bank Account$100$0-$100

Transferring money between two wallets

Let’s consider user 1 transferring $100 from their wallet to user 2’s wallet. Both wallets are liabilities to the business. We consider the following accounts:
AccountBalance
User 1 Wallet$200
User 2 Wallet$0
In the credit/debit model, the transaction would be:
AccountDebitCredit
User 1 Wallet$100$0
User 2 Wallet$0$100
Which would result in:
AccountBalance
User 1 Wallet$100
User 2 Wallet$100
By applying the golden rule, we get:
AccountSourceDestination
User 1 Wallet$100$0
User 2 Wallet$0$100
From this, we can derive the balance of the accounts:
AccountSourceDestinationBalance
User 1 Wallet$100$200$100
User 2 Wallet$0$100$100

Withdrawing money from a wallet

Let’s consider a merchant withdrawing $50 from their wallet to their bank account. The wallet is a liability, and the app bank account, from which we initiate the bank transfer, is an asset. We consider the following accounts:
AccountBalance
Merchant Wallet$100
Bank Account$1000
In the credit/debit model, the transaction would be:
AccountDebitCredit
Merchant Wallet$50$0
Bank Account$0$50
Which would result in:
AccountBalance
Merchant Wallet$50
Bank Account$950
By applying the golden rule, we get:
AccountSourceDestination
Merchant Wallet$50$0
Bank Account$0$50
From this, we can derive the balance of the accounts:
AccountSourceDestinationBalance
Merchant Wallet$50$100$50
Bank Account$1000$50$950

Treasury movement between two bank accounts

Let’s consider a business moving $250 from a bank account located in the US to a bank account located in the UK. Both bank accounts are assets to the business. We consider the following accounts:
AccountBalance
US Bank Account$1000
UK Bank Account$500
In the credit/debit model, the transaction would be:
AccountDebitCredit
US Bank Account$0$250
UK Bank Account$250$0
Which would result in:
AccountBalance
US Bank Account$750
UK Bank Account$750
By applying the golden rule, we get:
AccountSourceDestination
US Bank Account$0$250
UK Bank Account$250$0
From this, we can derive the balance of the accounts:
AccountSourceDestinationBalance
US Bank Account$1000$250-$750
UK Bank Account$750$0-$750
As we discussed above, asset accounts have a negative balance in the source/destination model.