Financial Accounting · §3.1

Ledger

The Accounting Equation & Double Entry

What a firm owns is financed by what it owes plus what its owners invested — no more, no less.

Definition 3.1.1 — The accounting equation

Assets = Liabilities + Owner's Equity

A firm's resources equal the claims against them — creditors' claims plus owners' claims.

Two sides, one balance

Assets = Liabilities + Equity equal width equal width

Both sides carry equal width — take in a resource and a matching claim appears with it.

Why it can't fall out of balance

One pool, counted twice.

Every entry moves both sides by the same amount — so the beam always holds level.

Definition 3.1.2 — Debits & credits

∑ Debits = ∑ Credits

A debit is an entry on the left; a credit, on the right. The words say only which side.

The bookkeeper's T-account

Cash Debit (Dr) $10,000 left side Credit (Cr) $10,000 right side

Debit left, credit right — equal amounts, so the entry balances.

The rules of increase

Assets rise left · Liabilities & equity rise right

An account's normal balance is simply the side that increases it.

Worked Example 3.1.1 — owner invests $10,000

+10,000 Assets = 0 + 10,000 Equity

Cash is debited, Owner's Capital credited — two accounts, equal and opposite.

Prove the books — the trial balance

$15,500 = $15,500

The debit and credit columns agree. Equality is necessary — not proof every account is right.

§3.1 — carry this forward

It balances.

Assets = Liabilities + Owner's Equity — true after every transaction, without exception.