How to use the running balance break finder
- Enter the balance before the first line you are checking.
- Paste the lines, each ending with the amount and then the balance after it. A date or note may come first. Spending is negative.
- Choose whether to trust the listed balance after a break or to keep your own running total.
- Read the lines where the balance does not follow, the size of each difference and the possible cause.
Formula
should be = balance before + amount
difference = listed balance - should be, in whole cents
a line breaks when the difference is not exactly zero
hints: balance equal to the balance before (amount never applied), balance equal to the balance before - amount (wrong sign), a difference that divides by 9 (digits may be swapped)
Trusting the listed balance restarts the check at each line, so every slip shows once. Keeping your own total shows the slip carried through every line after it.
A sample ledger with two slips
Starting from 1,200.00, the first five lines follow. On line 6 the amount is -45.50, so the balance should be 4,298.10 but is listed as 4,289.10. The difference is -9.00, which divides by 9, a sign that two digits may have been swapped.
On line 8 a refund of 64.00 should lift the balance to 4,314.85, but the listed balance is still 4,250.85, so the difference is -64.00 and the refund looks as if it was never applied. The sum of the differences is -73.00. Keeping your own total gives three breaks with differences of -9.00, -9.00 and -73.00, because the first slip is carried forward.
How to use the hints
The hints are common patterns, not proof. A difference of exactly the amount, or of twice the amount, often means the amount was left out or entered with the wrong sign. A difference that divides evenly by 9 is a classic sign of two neighboring digits being swapped, although many other differences divide by 9 by chance.
To dig further, test a difference with the Transposition Error Detector, find which items add up to an unexplained amount with the Subset Sum Reconciliation Finder, or reconcile against a statement with the Bank Reconciliation Template. Invoices have their own check in the Invoice Arithmetic Checker.
Why whole cents
Amounts are read as decimal text and held as whole cents, so there is no rounding error and 0.10 + 0.20 equals 0.30. Amounts with more than two decimals are refused, since a balance that carries fractions of a cent cannot be compared exactly.
Assumptions and limits
- Every line lists the amount and the balance after it, in that order at the end of the line.
- Lines are in the order the entries happened, and a blank line or a line starting with # is skipped.
- Amounts and balances have at most two decimals and may use commas, a dollar sign or brackets for negatives.
- Up to 5,000 lines are read, and nothing is uploaded.
Frequently asked questions
What if my statement has separate debit and credit columns?
Combine them first into one signed amount, with money out as negative. The tool needs a single amount per line.
Why does the line number count blank lines?
The number is the physical line in the box, so you can find it quickly. Blank lines and comments are skipped for the check but still counted in the numbering.
Can the tool find a missing line?
It shows where the balance stops following. A missing line looks like a break whose difference equals the amount that is missing, which you can then look for in the source.
What does keeping my own total do?
It carries each difference to the lines after it instead of restarting at the listed balance. Use it to see the total drift, and use the other choice to see where the separate slips are.