Define a static method in Python

Decorate a method with @staticmethod when it belongs with a class conceptually but does not need an automatically supplied instance or class argument. It receives only the arguments you explicitly pass.

Define and call it

class MathUtils:
    @staticmethod
    def add(a, b):
        return a + b

print(MathUtils.add(2, 3))    # 5
print(MathUtils().add(2, 3))  # 5

Calling through the class usually makes a stateless helper's role clearest. Calling through an instance is also valid and does not insert that instance into the argument list.

Compare method binding

class Demo:
    class_attr = "shared"

    def __init__(self):
        self.attr = "instance"

    def instance_method(self):
        return self.attr

    @classmethod
    def class_method(cls):
        return cls.class_attr

    @staticmethod
    def static_method(value):
        return value.upper()

Static methods are not forbidden from accessing other objects or class attributes. They simply receive no automatic self or cls. Referring to Demo.class_attr works, but hard-codes that class rather than following a subclass supplied as cls.

Group a parsing helper with a class

from datetime import datetime

class DateHelper:
    @staticmethod
    def is_valid_date(text):
        try:
            datetime.strptime(text, "%Y-%m-%d")
        except ValueError:
            return False
        return True

This helper expects a string and tests whether strptime can parse it as a date. It does not enforce a strict ten-character lexical format; some non-zero-padded components can parse. Add format validation if exact representation matters. A wrong input type can raise TypeError rather than returning false.

FAQ

Why not use a module function? That is often equally appropriate. A static method is an organizational choice, not a special runtime capability.

When should I use classmethod instead? Use it when the operation needs the class, especially cls(...) for an alternative constructor that should return a subclass instance.

Can a static method mutate an object? Yes, if an object is passed explicitly or otherwise available. Static binding does not make a function pure or read-only.

References

• Python functions reference
• Python functions reference
• Python datetime reference