Why Doesn't My Trial Balance Balance? Here's How to Find the Error
You entered everything. You ran the trial balance. The two columns don't match. Here's how to find out why — without re-checking every transaction one at a time.
By Antoine Joseph · Bookkeeping Basics · 6 min read
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A trial balance is just a list of every account and its balance, split into two columns — debits and credits. If your books are correct, both columns add up to the same total. If they don’t, something got recorded wrong somewhere. That’s the whole point of running one: it catches errors before they show up on your financial statements.
First: this is normal, not a sign you're bad at this
An out-of-balance trial balance happens to bookkeepers with decades of experience. It’s not a sign you’ve done something wrong in a bigger sense — it’s a sign the trial balance is doing its job. The error is almost always small and almost always findable in a few minutes once you know where to look.
Step 1: Find the difference between your two totals
Subtract the smaller total from the larger one. That difference is your biggest clue — before you check a single transaction, run it through these two quick tests.
Is the difference evenly divisible by 9?
Transposition error
If yes, you likely swapped two digits when copying a number — writing $1,593 as $1,539, for example. Swapping two adjacent digits always changes a number by a multiple of 9. A $54 difference (1,593 − 1,539) divided by 9 is 6, a clean division that confirms the pattern. Scan your entries for numbers that look “almost right.”
Is the difference evenly divisible by 2?
Wrong-side error
If yes, you likely have a balance that belongs in the debit column recorded as a credit, or vice versa. Divide the difference by 2, then look for an entry equal to that result — that’s usually your culprit, sitting on the wrong side.
Neither test hits? Move to the full checklist below.
Step 2: Work through the common causes, in this order
Check these from fastest to slowest — most trial balance errors are found in the first three.
- 1Re-add both columns. A simple addition mistake (accountants call this a “casting error”) is the most common cause of all, and the easiest to miss because you assume the math is fine.
- 2Confirm every account made it onto the trial balance. An omitted account — one that exists in your ledger but never got copied over — will throw off the total by exactly that account’s balance.
- 3Check that each balance landed in the right column. This is the wrong-side error from the divisible-by-2 test above.
- 4Look for transposed digits in any amount that seems slightly off from what you’d expect.
- 5Check for one-sided entries. Every transaction needs both a debit and a credit. If only one side got recorded in your journal, your trial balance won’t balance until the other side is added.
- 6Check for a transaction posted as two debits or two credits instead of one of each — less common, but it produces the same symptom as a one-sided entry.
What a trial balance can't catch
Here’s the part most explanations skip: a trial balance can balance perfectly and still be wrong. If you post an entire transaction to the wrong account — debiting Office Supplies instead of Equipment, but still balancing the debit against the right credit — your totals will match even though your books are inaccurate. A trial balance only proves your debits equal your credits. It doesn’t prove every entry landed in the correct account. That’s a separate check, and it’s why the trial balance is one step in the accounting cycle, not the whole thing.
If you're doing this from scratch, use a template instead of memory
Rebuilding a chart of accounts and trial balance from a blank page is where most of these errors start. Chart of Accounts Explained walks through the structure, and every template in the Tools Club ships with a built-in AI prompt — attach your finished file to ChatGPT or Claude and ask it to scan for exactly these patterns (transposition, wrong-side, one-sided entries) as a second opinion before you assume it’s fixed.
Sources
- OpenStax, Principles of Accounting, Volume 1: Financial Accounting — free, peer-reviewed textbook covering the trial balance and the full accounting cycle
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