What a journal entry is
A journal entry is the written record of a single transaction. It names the accounts involved, says how much value was recorded, and marks which side — debit or credit — each account is on. Think of it as the sentence accounting uses to describe an event. Every entry has the same three parts:
- Which accounts are affected (at least two).
- How much the amount is.
- Which side each account sits on — debit (left) or credit (right).
The steps, every single time
Recording any transaction is the same short routine. Walk through it slowly the first few times and it becomes automatic.
- What happened? Describe the event in plain words — “we paid rent,” “a customer paid us.”
- Which accounts does it touch? Every event hits at least two. One gives, one receives.
- Does each account go up or down? Decide the direction for each.
- Translate up/down into debit/credit. Use the account type to know which side that means.
- Check the balance. Debits on the left, credits on the right — and the two totals must match.
T-accounts in practice
A T-account is just a way to picture one account as a big letter T — debits on the left, credits on the right. A journal entry is what you get when you write down the matching halves of two (or more) T-accounts at once.
Example 1 — paying rent in cash
What happened: the business paid $1,000 for rent.
- It touches two accounts: Cash and Rent expense.
- Cash goes down — money left the business. Cash is an asset, so a decrease is a credit.
- Rent expense goes up — that’s what the money was for. Expenses increase with a debit.
Debits ($1,000) equal credits ($1,000). The entry balances. It reduces cash and recognizes rent expense for the period; both effects are on the record.
Example 2 — receiving payment for a cash sale
What happened: a customer paid the business $2,000 for a cash sale.
- It touches Cash and Revenue.
- Cash goes up — money arrived. Cash is an asset, so an increase is a debit.
- Revenue goes up — that’s where the money came from. Revenue increases with a credit.
Again, debits equal credits, and the money has a clear source and destination. Notice that Cash was debited this time and credited last time — same account, opposite directions, depending on whether money came in or went out. If the payment settles an earlier invoice, the credit is to Accounts Receivable rather than Revenue.
See also in Core BankingIn a ledger system a journal entry becomes a transaction made of operations — see How money moves and The building blocks.
In short
- A journal entry is how you actually record a transaction: which accounts, how much, and which side each is on.
- Follow the same steps every time — name the event, find the two accounts, decide up or down, translate to debit/credit, then check that the two sides balance.
- The iron rule never changes: debits must equal credits, which is what keeps every entry — and the whole ledger — trustworthy.
Next upEvery entry posts to an account — but where does that list of accounts come from? Meet the Chart of accounts.

