The Foundation of Double Entry
Double entry bookkeeping is based on the fundamental principle that for every financial transaction, at least two accounts are affected, and the total debits must equal the total credits.
The Dual Effect
Every transaction has a dual effect on the accounting equation:
When you record a transaction, the accounting equation must stay in balance.
Debit and Credit Rules
In accounting, "debit" refers to the left side of an account, and "credit" refers to the right side. The effect of debits and credits depends on the type of account:
| Account Type | Debit Effect | Credit Effect | Normal Balance |
|---|---|---|---|
| Asset | Increase | Decrease | Debit |
| Liability | Decrease | Increase | Credit |
| Equity | Decrease | Increase | Credit |
| Revenue | Decrease | Increase | Credit |
| Expense | Increase | Decrease | Debit |
T-Account Representation
T-accounts are a visual representation of individual general ledger accounts. The "T" format has debits on the left and credits on the right:
This T-account shows that Cash was debited for £5,000 (increasing the asset) and later credited for £1,500 (decreasing the asset).
Example Transaction
Let's look at a simple transaction: Purchasing equipment for £10,000 in cash.
Journal Entry:
| Account | Debit | Credit |
|---|---|---|
| Equipment | £10,000 | |
| Cash | £10,000 |
Analysis:
- Equipment (asset) increases, so it's debited.
- Cash (asset) decreases, so it's credited.
- The total debits (£10,000) equal the total credits (£10,000), keeping the accounting equation in balance.
The Golden Rules
- Debit what comes in, Credit what goes out
- Debit the receiver, Credit the giver
- Debit all expenses and losses, Credit all incomes and gains
Why This Matters
The debit and credit system provides:
- A built-in error detection mechanism (debits must equal credits)
- A complete record of how every transaction affects the business
- The foundation for accurate financial reporting