Debits and Credits: The Rule That Finally Makes Sense
- Start with the equation
- Deriving the rule
- Where income and expenses come from
- Six transactions people get backwards
- Why bank statements confuse everyone
- Checking yourself
- Where this fits
Most people are taught debits and credits as a mnemonic and never recover. The mnemonics work until a transaction does not fit one, and then there is nothing underneath to fall back on.
There is something underneath. The rule is not arbitrary; it falls straight out of one equation, and once you have derived it you stop needing to remember it.
Start with the equation
Assets = Liabilities + Equity
Everything the business controls, on the left. Everyone’s claim on it, on the right. Owners have a claim and so do lenders and suppliers. The equation holds after every single transaction, without exception, because it is a description of the same pile of value counted two ways.
Now the only convention you have to accept: debit means the left side, credit means the right side. That is all those words mean. They are not good and bad, nor increase and decrease, nor money in and money out. In bookkeeping they are simply the names for the left and right sides of an account.
Deriving the rule
Assets live on the left of the equation. So an asset increases on the left, which is a debit.
Liabilities and equity live on the right. So they increase on the right, which is a credit.
Decreases are the opposite in each case. That is the entire rule:
| Account type | Increases with | Decreases with |
|---|---|---|
| Asset | Debit | Credit |
| Liability | Credit | Debit |
| Equity | Credit | Debit |
Three rows, derived rather than memorised. Everything else follows.
Where income and expenses come from
Income and expenses are not a fourth and fifth category. They are equity, opened up so you can see what happened during the year.
Profit increases what the owner is owed. So income increases equity, and therefore credits. Expenses reduce profit and so reduce equity, and therefore debit.
That is why revenue has a credit balance and rent has a debit balance, and why it is not a separate fact to learn. Expand the table only if it helps:
| Account type | Increases with | Normal balance |
|---|---|---|
| Asset | Debit | Debit |
| Expense | Debit | Debit |
| Liability | Credit | Credit |
| Equity | Credit | Credit |
| Income | Credit | Credit |
Six transactions people get backwards
1. A customer pays an old invoice, ₹50,000.
Cash goes up: Dr Cash ₹50,000. The receivable goes away, and a receivable is an asset, so it decreases with a credit: Cr Trade receivables ₹50,000.
No income. The sale was recorded when it was made. This is the one people get wrong most often, and the tell is that recording income here would count the same sale twice.
2. You take a ₹5,00,000 bank loan.
Dr Bank ₹5,00,000 · Cr Bank loan ₹5,00,000. Cash rose and so did an obligation. Borrowing is not income, however much better the bank balance looks.
3. The owner withdraws ₹40,000 for personal use.
Dr Drawings ₹40,000 · Cr Bank ₹40,000. Drawings reduce equity, so they debit. This is not a business expense and never reaches the profit and loss account.
4. You buy stock on credit, ₹1,20,000.
Dr Purchases ₹1,20,000 · Cr Trade payables ₹1,20,000. No cash moved. The obligation is what changed, and a liability increases with a credit.
5. Depreciation of ₹60,000.
Dr Depreciation ₹60,000 · Cr Accumulated depreciation ₹60,000. An expense debits. The credit does not go to the asset directly but to a contra account that sits against it, so you keep both the original cost and the wear.
6. A customer pays ₹2,00,000 in advance for work not yet done.
Dr Bank ₹2,00,000 · Cr Advance from customer ₹2,00,000. Cash arrived but you owe the work, so the credit goes to a liability. Treating this as income is how businesses report profits they have not earned.
Why bank statements confuse everyone
Your bank statement shows deposits as credits. Your books show the same deposit as a debit to bank. Both are right, and the reason is that they are written from opposite sides.
The bank owes you your balance, so in the bank’s books your account is a liability. Money in increases what they owe you, which credits it. In your books, that bank balance is an asset, so money in debits it.
Once you see that the statement is the bank’s ledger and not yours, the contradiction disappears. It is also why bank reconciliation is a real task rather than a formality.
Checking yourself
Two tests catch most errors before they travel.
Does the equation still hold? After the entry, do the two sides still agree? If an entry debits two accounts and credits none, something is missing.
Does the balance have the sign it should? A cash account with a credit balance means you have spent money you do not have, which is either an overdraft or an error. A revenue account with a debit balance means a sale was reversed, or an entry went the wrong way. Balances in the wrong direction are the fastest diagnostic in bookkeeping.
If a transaction genuinely resists, ask the two questions in order: what did the business get, and what did it give up? The thing received is almost always the debit.
Where this fits
- The lesson version: debits and credits
- Where the equation comes from: accounting basics
- These entries in a full period end: from trial balance to balance sheet
- Where the bank statement fits: bank reconciliation
- Terms used here: accounting glossary