Opening Balance Calculator

The opening balance is the amount sitting in an account when a new period begins. It is the number every later transaction is measured against: deposits add to it, withdrawals subtract from it, and the closing balance is whatever remains when the period ends. Getting it right matters, because every reconciliation, budget, and cash-flow statement starts from this single figure.

This Opening Balance Calculator works the accounting formula backwards. Give it the closing balance plus the deposits and withdrawals that happened during the period, and it recovers the opening balance instantly, showing each step of the arithmetic. Flip to reverse mode and it runs the check the other way, rebuilding the closing balance from the opening figure so you can confirm the books tie out. Every number on this page was verified in the tool itself.

How the opening balance formula works

Every accounting period obeys one simple relationship: the money you end with equals the money you started with, plus what came in, minus what went out. Written out, that is Closing = Opening + Deposits − Withdrawals. The opening balance calculator simply runs that relationship backwards. Subtract the deposits, add back the withdrawals, and the closing balance unwinds to the figure the period started with: Opening = Closing − Deposits + Withdrawals.

The sign pattern trips people up, so here is the intuition. Deposits inflated the closing balance, which means they must be removed to find the start. Withdrawals shrank the closing balance, which means they must be added back. The tool shows the substituted formula with your numbers on every result, and the reverse check at the bottom re-derives the closing balance from the answer, so any data-entry slip shows up immediately as a mismatch.

Reverse mode flips the direction for the other common job: projecting where an account will land. Enter the opening balance, expected deposits, and planned withdrawals, and it computes the closing balance directly. If you are tracking how interest changes a balance over time rather than reconciling a period, our daily interest calculator handles the interest side, and the ending balance calculator covers the forward projection in more depth.

Worked example, verified in the tool

A small business closes March with $15,000.00 in its checking account. During March it received $2,350.00 in customer deposits and paid out $1,120.00 in expenses. To find the February closing figure that March started from:

Opening = $15,000.00 − $2,350.00 + $1,120.00 = $13,770.00.

The reverse check confirms it: $13,770.00 + $2,350.00 − $1,120.00 = $15,000.00, exactly the closing balance entered. Run these three numbers through the calculator above and you will get the same $13,770.00 headline, the same substituted formula, and the same passing check.

When this calculation comes up

Bank reconciliation. A statement shows the closing figure; your cash book shows the transactions. Reversing the period's deposits and withdrawals is how you confirm the opening figure both records agree on. The Corporate Finance Institute walkthrough of the bank reconciliation process (linked below) shows where this step sits.

Starting fresh books. A new business, or one moving to new accounting software, needs a correct opening figure for every account before the first transaction is posted. An error here compounds through every later report.

Cash drawer and till counts. Retailers compare the drawer total against the float they started with plus sales minus payouts. Solving for the float answers "did the drawer start the day correctly?"

Savings tracking. When a savings account earns interest through the period, the interest acts like an extra deposit in the formula. Pair the result with our daily compound calculator to separate genuine growth from the interest the bank added, or use the percent growth calculator to express the change as a rate.

What competing tools miss

This keyword has surprisingly thin tool coverage, and what ranks mostly answers a different question:

• Credit-card "new opening balance" tools compute balance plus finance charge, which is a lender-specific formula for revolving credit, not the general accounting reversal. They cannot solve for an opening balance from deposits and withdrawals.
• Exam Q&A pages and SAP documentation explain the concept in words but give you no calculator at all; you still do the arithmetic by hand.
• No ranking page offers the reverse direction. This tool's second mode computes the closing balance from the opening figure, and every result carries a built-in verification line that re-derives the input. If a single digit is mistyped, the check fails visibly instead of silently.
• Inline validation instead of pop-ups. Empty or negative entries get a clear on-screen message next to the tool, and the Copy and Share buttons sit side by side in the results panel so the reconciled figures travel with your records.

Frequently asked questions

What is an opening balance in accounting?

It is the balance of an account at the start of a financial period, carried forward from the previous period's closing balance. It is the first entry in the period's records, and every transaction during the period is measured against it.

What is the formula for opening balance?

Opening Balance = Closing Balance − Deposits + Withdrawals. Subtract everything paid in during the period and add back everything paid out, and the closing figure unwinds to the starting figure.

What is the difference between opening balance and closing balance?

The opening balance starts the period; the closing balance ends it. They are linked by the period's activity: closing equals opening plus deposits minus withdrawals. In continuous records, one period's closing balance becomes the next period's opening balance.

Can the opening balance be negative?

Yes, for example an overdrawn bank account or a loan account starts the period negative. The formula still works: a negative opening balance plus net deposits gives the closing figure. This tool asks for non-negative inputs for the common reconciliation case; handle overdrafts by keeping the signs consistent in your own books.

Why does my calculated opening balance not match my records?

The usual causes are a missing transaction (an unrecorded deposit or withdrawal), a transposed digit, or mixing periods by including a transaction from the wrong month. The reverse check on each result re-derives the closing balance, so a mismatch there points straight at the inputs rather than the math.

Do outstanding checks affect the opening balance?

Only through timing. A check written but not yet cleared is still a withdrawal of the period for your books, so include it in withdrawals even though the bank statement does not show it yet. That timing gap is exactly what bank reconciliation exists to explain.