Closing the books transfers the balances of temporary accounts (revenues, expenses, dividends/draws) into retained earnings, resetting them to zero for the next period. This is the final step in the accounting cycle before the post-closing trial balance.

Steps:

  1. Close revenue accounts. Debit each revenue account for its balance, credit Income Summary.
  2. Close expense accounts. Credit each expense account for its balance, debit Income Summary.
  3. Close Income Summary. If Income Summary has a credit balance (net income), debit Income Summary and credit Retained Earnings. If it has a debit balance (net loss), credit Income Summary and debit Retained Earnings.
  4. Close dividends/draws. Debit Retained Earnings, credit Dividends.
  5. Prepare a post-closing trial balance. Only permanent accounts (assets, liabilities, equity) should remain. All temporary accounts should show zero.

Worked example: Service Revenue has a 12,000 debit balance. Rent Expense has a 2,000 debit balance.

AccountDebitCredit
Service Revenue$20,000
Income Summary$20,000
AccountDebitCredit
Income Summary$15,000
Wages Expense$12,000
Rent Expense$3,000

Income Summary now has a $5,000 credit balance (net income).

AccountDebitCredit
Income Summary$5,000
Retained Earnings$5,000
AccountDebitCredit
Retained Earnings$2,000
Dividends$2,000

After closing, all temporary accounts are zero and Retained Earnings increased by 5,000 income minus $2,000 dividends).

Why this matters: Without closing entries, revenue and expense balances would accumulate across periods, making the income statement meaningless — it would show all-time totals instead of the current period.