---
title: SSF Number Formatter
hide_table_of_contents: true
pagination_next: constellation/frac/index
---
As explained in ["Number Formats"](/docs/csf/features/nf), modern spreadsheet
file formats separate "content" from "presentation". Instead of storing a
formatted value like `$3.50`, applications will store the underlying value
(`3.50`) and the number format (`$0.00`). Parsers are expected to render values.
The SheetJS `SSF` ("SpreadSheet Format") library formats numbers according
to the number formatting rules defined in Excel and other spreadsheet software[^1]
A version of the library ships with the main file processing library. It is
deeply integrated in SheetJS CE API functions including `read`[^2], `write`[^3],
and `sheet_to_json`[^4].
The library is also available for standalone use on the SheetJS CDN[^5].
Source code and project documentation are hosted on the SheetJS Git server at
https://git.sheetjs.com/sheetjs/sheetjs/src/branch/master/packages/ssf
## Live Demo
The formatted text is calculated from the specified number format and value.
Please [report an issue](https://git.sheetjs.com/sheetjs/sheetjs/issues) if a
particular format is not supported.
```jsx live
function SheetJSSSF() {
const [fmt, setFmt] = React.useState("#,##0");
const [val, setVal] = React.useState(7262);
const [text, setText] = React.useState("");
React.useEffect(() => {
if(typeof SSF == "undefined") return setText("ERROR: Reload this page!");
let v = +val;
if(!isFinite(v)) return setText(`ERROR: ${val} is not a valid number!`);
try {
setText(SSF.format(fmt, v));
} catch(e) { setText("ERROR: " + (e && e.message || e)); }
}, [fmt, val]);
const goodstyle = { backgroundColor: "#C6EFCE", color: "#006100" };
const badstyle = { backgroundColor: "#FFC7CE", color: "#9C0006" };
return (
Number Format
setFmt(e.target.value)}/>
Number Value
setVal(e.target.value)}/>
Formatted Text
{text}
);
}
```
[^1]: The number formatting rules are sketched in ECMA-376. A rough grammar is defined in the MS-XLS specification.
[^2]: See [`read` in "Reading Files"](/docs/api/parse-options)
[^3]: See [`write` in "Writing Files"](/docs/api/write-options)
[^4]: See [`sheet_to_json` in "Utilities"](/docs/api/utilities/array#array-output)
[^5]: See https://cdn.sheetjs.com/ssf/ for more details.