To Round or Not to Round?

Exploring the Quiet Complexity Behind Financial Presentation

After reviewing the ASX Top 20 reports using the Accurate Digits platform, one thing became clear: rounding isn’t as consistent, or as simple, as you might think.

In the world of financial reporting, rounding is one of those small decisions that quietly turns into a big one. It shapes how reports are read, how quickly they’re finalised, and how confidently the numbers hold up to scrutiny.

So, who’s doing it right?

The truth is, there’s no single right answer. But how you round (or don’t) says a lot about your company’s approach, and has more impact than most people realise.

🧾 This Isn’t About ASIC’s Rounding Rules

Let’s get one thing clear upfront.

This isn’t about ASIC Corporations Instrument 2016/191, which permits companies to round figures in financial reports to the nearest thousand or million.

We’re talking about something else — the actual presentation of numbers in tables and calculations, including subtotals and supplementary data disclosed in your reports and ASX filings.

🧠 WiseTech: No Rounding, No Guesswork

Extract from the Consolidated statement of profit or loss and other comprehensive income, page 10 of WiseTech Global 1H25 Appendix 4D and financial report released 26 February 2025

WiseTech applies ASIC Instrument 2016/191 to round to the nearest million, including one decimal place. But the key difference? They don’t manually adjust subtotals to “make them fit.”

In this example, gross profit for the half-year to 31 December 2024 is reported as $324 million. But if you subtract cost of revenues ($57.1m) from revenue ($381.0m), you only get $323.9 million — a rounding difference of $0.1 million.

This isn’t an oversight. It’s an intentional choice: WiseTech does not adjust for rounding throughout their financial report.

At first glance, it might feel abrupt. But the experience is surprisingly clean. Every number is shown as-is. Totals might be off by a tenth, but they reflect the data honestly.

The payoff? Time saved.
No one’s patching rounding issues, reconciling mismatches across disclosures, or triple-checking narrative tables in the Directors’ Report.
The team can focus on what actually matters.

🛢️ Rio Tinto: Rounded Figures, Precise Percentages

Extract from Underlying EBITDA and underlying earnings by product group, page 7 of Rio Tinto 2024 half year results released 31 July 2024

Rio Tinto takes a different path — and it's a bit more nuanced.

In the above extract (outside the financial statements and Directors’ Report), values are visually rounded, but the percentages shown reflect the unrounded base values.

You’ll notice:

• Subtotals (highlighted in blue) are out by 0.1 — a clear rounding difference
• The change percentages (highlighted in yellow) don’t match the displayed numbers if you recalculate them manually

That’s because the percentage changes are based on the actual values, not the rounded ones shown in the table. This makes the growth rates more accurate — but also impossible to reconcile if you’re using the report alone.

It’s not misleading. In fact, it's technically more precise, but it can confuse a reader who tries to back-solve and can’t reconcile the math.

🌀 The Mixed Model: Rio Tinto’s Rounded View

Extract from note 3. Segmental information, page 38 of Rio Tinto 2024 half year results released 31 July 2024.

The story shifts once you step into Rio Tinto’s audited financial statements.

Here, the tables take a more traditional form. Every figure is rounded — but carefully so. Subtotals add cleanly. There are no awkward decimals or percentages that don’t quite line up. It’s tidy, consistent, and clearly reconciled.

That’s in sharp contrast to the approach used in the “Other Information” sections, where rounding feels more like a visual overlay — as if the numbers were formatted in Excel, but not actually rounded behind the scenes. Subtotals in those tables often don’t match precisely, and percentages can’t always be recalculated from the numbers shown.

It’s a deliberate contrast. One style prioritises precision in movements and growth rates, even if it’s a little harder to follow. The other leans into visual clarity — especially in the parts of the report subject to audit.

Neither approach is wrong. But together, they highlight a quiet truth:

Rounding isn’t just a formatting choice — it’s part of the story you’re telling.

⚖️ So… What’s the Right Approach?

The short answer? There isn’t one.

All approaches are acceptable. There doesn’t appear to be any obvious requirements in breach of standards, audit protocols, or ASIC rules if you choose either method. Otherwise the big four auditors would not have signed off in these instances.

But there are trade-offs:

🕰️ The Hidden Cost of Rounding

Getting rounding “just right” is often a hidden time sink. It rarely shows up on the timeline — but every CFO and Financial Controller knows the drill:

• Fix a subtotal that’s off by 1 (or even just 0.1), which means adjusting or hiding a value to smooth it out
• Update any percentage calculations tied to that figure, so they still make sense
• Cross-check that everything still reconciles with other disclosures or summary tables
• Then triple-check it all to make sure nothing else was thrown off in the process

All of this effort — to solve a “problem” that technically isn’t even an error.

Rounding might seem cosmetic, but it quietly consumes hours — especially in the final stretch before release.

🛠️ So… Should You Round?

That’s your call.

Rounding is a reporting design choice — and it affects how your numbers are read, interpreted, and trusted.