Journalizing and Posting

It starts with a piece of paper

In the last guide you learned to turn an event into a balanced journal entry. But where does the event come from — and how do you know it really happened? A bookkeeper does not record rumors. Every entry begins with a source document: a physical or digital scrap of evidence that a transaction occurred. A receipt for cash paid, an invoice sent to a customer, a voucher authorizing a payment, a bank statement, a payroll register — each one is the paper trail that says, in effect, *this is real, and here are the numbers*. The source document is the seed; the entry is what grows from it.

The document does more than prove the amount; it answers the four questions you already know how to ask. Read a coffee-shop sales slip and it hands you the accounts (Cash and Sales Revenue), the direction (cash in, revenue earned), the amount (say 50 dollars), and the date — everything a journal entry needs. This is why accountants are almost obsessive about keeping documents: an entry without a document behind it is a claim with no witness. When an auditor later asks *prove this number*, the source document is the answer. No paper, no proof.

Two books, two purposes

Once an entry is written, it lives in two places in turn, and the difference between them is the heart of this guide. First it goes into the general journal — the chronological book, organized strictly by date. The journal is wonderful for telling a story in order ("on the 3rd we paid rent, on the 5th we made a sale, on the 7th we bought supplies"), but it is useless for answering the one question an owner asks every day: *how much cash do I actually have right now?* To find that, you would have to flip through every page hunting for the word Cash and add it all up by hand.

So the same numbers are copied into a second book, the general ledger, which is organized the opposite way: by account, not by date. The ledger gives every account in the chart of accounts its own page (its own T-account, conceptually), and gathers onto that page every debit and credit that ever touched it. Now the question is trivial: turn to the Cash page, net the debits against the credits, and the account balance is right there. The journal and the ledger hold exactly the same facts — they are two filing systems for one set of events. The journal sorts by *when*; the ledger sorts by *what*.

A useful image: the journal is your diary, written line by line as the day unfolds; the ledger is your address book, where you can flip straight to one name and see every dealing you have ever had with them. The diary preserves sequence; the address book preserves totals. You need both, because they answer different questions — and copying faithfully from the first into the second is the entire skill of posting.

Posting: copying the numbers across

Posting is the mechanical act of transferring each amount from a journal entry to its account in the ledger. It is deliberately dull: you are not deciding anything new — every judgment was already made when you journalized. A debit in the journal becomes a debit on the ledger page; a credit becomes a credit. You never flip a side during posting. If you debited Cash 50 in the journal, you write 50 on the debit side of the Cash page — same account, same side, same amount. Posting is pure copying, and any creativity here is a bug, not a feature.

Follow one entry all the way across. On July 3 a shop sells 50 dollars of goods for cash, so the journal reads: debit Cash 50, credit Sales Revenue 50. Posting splits this single entry into two destinations. The 50-debit goes to the Cash page in the ledger; the 50-credit goes to the Sales Revenue page. Notice that the entry, which was one tidy unit in the journal, is deliberately torn apart in the ledger — each half flies off to live with its own account. That is the whole point: the ledger regathers the halves by account so balances can form.

JOURNAL (by date)               LEDGER (by account)
--------------------------      ----------------------------
Jul 3  Cash         50           CASH
          Sales Revenue 50         Dr |  Cr
       (Cash sale)                 50 |
                                ----------------------------
                                  SALES REVENUE
                                   Dr |  Cr
                                      |  50

Cross-referencing: the trail both ways

Copying the numbers is only half of good posting; the other half is leaving a trail. When you post, you also record a cross-reference in two directions at once. Beside the journal line you note the ledger account number you sent the amount to; on the ledger page you note the journal page the amount came from. (In old hand-kept books this paired notation had a name — the *posting reference* or folio column.) The result is that any number, anywhere in the system, carries a tiny pointer to its twin in the other book.

This two-way pointer is the audit trail, and it earns its keep constantly. Reading the ledger and puzzled by a 50 on the Cash page? The reference walks you back to the exact journal entry, which carries the narration and the source-document number — so you can trace the figure all the way home to the original receipt. Working forward instead? From a single receipt you can find its journal entry and then every ledger account it fed. The chain — source document, journal entry, ledger posting — is walkable in either direction, and that walkability is precisely what makes the books trustworthy rather than merely tidy.

The full path, and where it goes next

Step back and the whole movement is one clean pipeline, and the same four moves repeat for every transaction a business ever has.

1. A transaction happens and produces a source document — a receipt, an invoice, a voucher — the evidence that anything occurred at all.
2. Read the document and journalize: write a dated, balanced entry into the general journal, in time order.
3. Post: copy each amount to its account in the ledger, debit to debit and credit to credit, never flipping a side.
4. Cross-reference both ways so any figure can be traced backward to its source or forward to every account it reached.

One honest reminder before we move on: this pipeline is faithful, not infallible. Posting copies whatever the journal says, so a wrong account chosen back at journalizing time sails through untouched — the ledger will dutifully misfile a correct number under the wrong name. And a posting that balances does not prove the right accounts were used; it only proves the arithmetic survived the copying. The pipeline guarantees that what you recorded is carried through cleanly. It cannot guarantee that what you recorded was true. That second kind of checking is a human job, which is exactly why the audit trail matters.

Once every entry has been posted, each ledger account carries an up-to-date balance — and the accounting cycle is ready for its next checkpoint. The natural question becomes: across all those accounts, do the total debits still equal the total credits, as double-entry promised? Listing every account balance side by side to test exactly that is the trial balance, and it is where the next guide picks up the trail.