Can’t get bank reconciliation to balance?

You’ve looked over it a hundred times and can’t see any error, but it’s still out by $36 (or $18, or $0.27),

Has this ever happened to you when trying to reconcile a bank account, supplier account, petty cash or merchant facility? After staring at the numbers and checking over and over, it can feel like you’re going around in circles.

You’re frustrated, you’re wasting time and brain-power trying to figure it out, and getting nowhere.

There can be a good explanation for this. It’s not always the case but this is a handy rule-of-thumb you can use so you don’t waste time.

Two numbers around the wrong way can be hard to spot because often our eyes take in the number but jumble them up in our brain so we see $235 as $253 without realising. This is a real thing; it’s called a Transposition Error.

Transposition Error

In data entry, two numbers around the wrong is a “transposition error”. The error will always be a number that can be equally divided by the number 9.

Examples without decimals:

$235 – $253 = $18 / 9 = 9

$1,845 – $1,584 = $261 / = 29

$268,179 – $286,179 = $18,000 / 9 = 2,000

See how once divided by 9 it’s always an EVEN number? If it’s not a transposition error then it


Examples of data entry mistake that will not be a transposition error.

$235 – $233 = $2 / 9 = 0.2222

$1,845 – $1825 = $20 / 9 = 2.2222

$268,179 – $268,779 = -$600 / 9 = -66.6667

See how when divided by 9 it’s not an even number?

Examples with decimals:

When there are decimals you can still have a transposition error. To work it out you take the amount you are out of balance by, get rid of the decimals, then divide it by 9.

$20.56 – $20.65 = $0.09 = 9 / 9 = 1

$185.51 – $185.15 = $0.36 = 36 / 9 = 4

How do these errors happen?

It is most likely to happen when entering data manually. As humans, we can easily make a mistake and not notice, especially if the numbers look similar. If we are tired, stressed or have been working on it a long time it is more likely.

What’s the problem?

Sometimes the errors are relatively small, so does it really matter?

Yes and no. If the error is out by $180 or $2,700, or $36,000 then obviously that is a huge issue. Perhaps when writing a cheque or processing a bank payment this could potentially happen. But it’s less likely.

What is the error is only $0.36 or $18 then it’s not a big deal, right? But how about the time spent trying to discover the error? How much is that costing you? If you spend 20 minutes looking for this error and your hourly rate is worth $50 then you have just spent $16 on that one error. This can add up over time which is why it is important to know this basic reconciliation skill to potentially save a lot of time and money.

Does it always work?

If your balance is out by $36 then is it definitely a transposition error? It’s likely but no, not always. Let’s say there are two errors;

One item for $18 is entered as $16 = $2

and a missing entry or line item of $34

Add the two errors together, $2 + $7 = $9 / 9 = 1

This is not a transposition error.

So as you can see this small test is just one place to look of many possibilities. But it is always worth checking as it only takes a few seconds to do so which could save you many minutes or even hours.

All the best with your reconciling endeavours. Please contact me if you have any questions.

Amy Hooke is a bookkeeping industry professional who helps business owners to feel more organised and achieve their dream of a “paperless office”.

Amy also founded, a marketing and web design agency for bookkeepers; to help them feel more confident about marketing.