str.isnumeric()

str.isnumeric()

Returns: bool · Added in v3.x · Updated March 13, 2026 · String Methods

stdlib string validation

The isnumeric() method checks whether all characters in a string are numeric characters and the string contains at least one character. It returns a boolean value—True if every character has a numeric value property in Unicode, False otherwise.

This method is useful when you need to validate numeric input that might include Unicode characters like fractions, roman numerals, or subscript/superscript digits.

Syntax

str.isnumeric()

Parameters

This method takes no parameters.

Examples

Basic usage

>>> "12345".isnumeric()
True
>>> "12.34".isnumeric()
False
>>> "".isnumeric()
False
>>> "abc".isnumeric()
False

Unicode numeric characters

Python 3 supports various Unicode characters that have numeric value properties:

>>> "Ⅶ".isnumeric()    # Roman numeral seven
True
>>> "ⅱ".isnumeric()    # Small Roman numeral two
True
>>> "½".isnumeric()    # Vulgar fraction one-half
True
>>> "²".isnumeric()    # Superscript two
True

Characters that fail

>>> "12.34".isnumeric()   # Decimal point
False
>>> "-50".isnumeric()     # Minus sign
False
>>> "1,000".isnumeric()  # Comma
False
>>> "  123".isnumeric()  # Leading space
False

Common Patterns

Validating numeric input with Unicode support

def extract_numeric(text):
    """Extract all numeric characters from a string."""
    return ''.join(c for c in text if c.isnumeric())

>>> extract_numeric("Room 302B")
'302'
>>> extract_numeric("Call 555-1234")
'5551234'
>>> extract_numeric("Price: €50½")
'50½'

Processing international numeric data

def is_numeric_entry(value):
    """Check if entry contains only numeric characters."""
    return value.isnumeric() and len(value) > 0

>>> is_numeric_entry("123")
True
>>> is_numeric_entry("ⅠⅡⅢ")  # Roman numerals
True
>>> is_numeric_entry("①②③")  # Enclosed numbers
True
>>> is_numeric_entry("")
False

Differences Between isdigit, isnumeric, and isdecimal

These three methods have subtle but important differences:

Method	Accepts	Example
`isdigit()`	0-9, superscripts	`²` → True
`isnumeric()`	isdigit() + fractions + Roman numerals	`½` → True, `Ⅶ` → True
`isdecimal()`	0-9 only (strict)	`½` → False

>>> "²".isdigit(), "²".isnumeric(), "²".isdecimal()
(True, True, False)
>>> "½".isdigit(), "½".isnumeric(), "½".isdecimal()
(False, True, False)

Behavior Notes

Returns False for empty strings—the string must contain at least one character
Accepts any Unicode character with numeric value property (Nd, Nl, No categories)
Does not accept minus signs, decimal points, commas, or other numeric punctuation
Roman numerals are considered numeric (category Nl)
Fractions like ½ and ⅕ are considered numeric