Number Format Checker

Find the places where a document is inconsistent about numbers — mixed decimal separators, mixed thousands grouping, ambiguous values like 1.500, percent spacing and currency placement — and rewrite them in one convention.

What is Number Format Checker?

Number formatting is invisible until it is wrong, and then it is dangerously wrong. A report that writes 1,234.56 in one paragraph and 1.234,56 in the next is asking every reader to interpret two conventions at once, and an international reader may read them as different values. The Number Format Checker scans a document, works out how each number is punctuated, and reports the inconsistencies in plain language.

Detection is rule-based and the rules are stated. Each numeric token is analysed for a decimal separator, a thousands separator, a sign, a currency symbol, a percent sign and a trailing unit. The analyser then looks for genuine problems: both a comma and a full stop used as decimal separators; both used for grouping; values such as 1.500 that are legitimately ambiguous; grouping that is not standard three-digit; large ungrouped numbers; percent signs spaced inconsistently; currency symbols appearing both before and after amounts; more than one currency in the same text; and units written both with and without a space after the number.

Ambiguity is reported rather than resolved. "1.500" is fifteen hundred if the document is using a dot as a grouping separator, and one and a half if it is using a dot as a decimal separator. Both readings are legal, so the tool reports the token as ambiguous and tells you which reading it used for the value column instead of picking silently. The same honesty applies to Indian lakh and crore grouping: "1,23,456" is valid in en-IN and irregular in en-US, so the finding is labelled informational.

The interpretation table shows every number the scanner found, with the value it inferred and the separators it saw. That is the audit trail: if the analyser read something differently from how you meant it, you can see exactly which token and why, rather than arguing with a black box.

Finally, the tool rewrites the whole document in one convention — US and UK style with 1,234,567.89, European style with 1.234.567,89, or SI and French style with narrow spaces — and shows the rewritten text ready to copy. Numbers the author wrote without separators and that are four digits or shorter are left alone, because regrouping a year into "2,026" changes what the sentence says. Currency symbols, signs, percent signs and units keep their original position; only the digit punctuation moves. The same interpretation engine backs the {{number-locale-formatter|Number Locale Formatter}}, which renders a single value in any locale's conventions, and mixed-script documents benefit from a pass through the {{unicode-text-normalizer|Unicode Text Normalizer}} to remove invisible characters that can hide inside pasted numbers.

The findings are ordered so a long document stays readable: whole-document structural issues first, then per-number observations in document order, each carrying the surrounding context so the line can be found. Nothing is rewritten until you ask for it, which matters when a draft combines a price list in one convention with body text in another. The checker reports the mixture and the normalizer applies your chosen convention to the numbers, leaving every other character of the sentence — including the words around the figures — exactly as the author wrote it.

How to use Number Format Checker

1. Paste the document that contains numbers.
2. Read the consistency issues list; each finding names the kind of problem and quotes the context.
3. Check the interpretation table for any number marked ambiguous or irregular, and confirm the value column matches what you meant.
4. Choose the convention you want in the rewrite dropdown.
5. Copy the rewritten text or download it as a file, then diff it against your original before publishing.

When to use Number Format Checker vs related tools

Use the checker before publishing anything that mixes sources: a report assembled from several contributors, a translation handed between teams, or a dataset description written by someone using a different locale. It is also the fastest way to audit a document for the specific ambiguity of numbers like 1.500.

When you need to render one value correctly for a specific locale rather than audit a document, use the Number Locale Formatter, which is built on the same parsing rules. When the document is predominantly about dates and times rather than amounts, the Locale Date Formatter covers that convention family in the same way.

Privacy & Security

This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.

Frequently asked questions about Number Format Checker