Running balance calculator
Plenty of exports arrive without a balance column: credit card CSVs, some app-bank exports, rows retyped by hand. Paste the rows, give the opening balance, and this tool rebuilds the running balance to the penny so you can compare the closing figure against the statement and paste the column back into your sheet.
Runs in this browser tab. Nothing you paste or open here is uploaded.
Limitations
- The result is only as good as the opening balance and the rows: a wrong opening figure shifts every balance by the same amount, and a missing row shifts everything after it.
- Amounts must be readable as money; rows without any amount (markers, notes) are skipped and reported rather than treated as zero.
- This tool builds the balance column; to find where an existing balance column first disagrees with the amounts, use the statement balance checker instead.