Number.toPrecision() Format with significant digits
Last updated: 2026-09-09
Number.toPrecision() Format with significant digits
toPrecision formats a number to a specified number of significant digits.
| Category | Numbers |
|---|---|
| ES version | ES3 |
📝 Syntax
const str = number.toPrecision(digits);⚙️ Parameters
| digits | Optional. Significant digits 1~100; omitted = toString(). |
|---|
Returns：A formatted string.
Mutates the original：No (returns a new value)
▶ Example
Edit the code, press Run, and see the result in the output panel:
Output：
123.5
1.2e+2
123.456💡 Tip toPrecision uses significant digits; toFixed uses decimal places.
⚠️ Warning Switches to scientific notation when integer part exceeds digits.
🌐 Browser support
| Browser |  Chrome |
 Edge |
 Firefox |
 Safari |
 Opera |
|---|---|---|---|---|---|
| Number.toPrecision() | ✓ v1 | ✓ v12 | ✓ v1 | ✓ v1 | ✓ v1 |
| Supported by all modern browsers | |||||
🏷️ Related Items
💡 Related Cases
More case studies coming soon — check back later.
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❓ FAQ
QtoPrecision vs toFixed?
AtoPrecision = significant digits; toFixed = decimal places.
QScientific notation?
AYes, when integer part exceeds available digits.
QtoPrecision(6) on 123.456?
AReturns '123.456' — exactly 6 significant digits.
