What is the maximum possible value of an integer in Python?

Python has different integer limits depending on the version. In Python 2, integers had a maximum value before switching to long type, but Python 3 has unlimited precision integers bounded only by available memory.

Python 2 Integer Behavior

In Python 2, integers automatically switched to long type when they exceeded their limit ?

import sys
print(type(sys.maxint))
print(type(sys.maxint + 1))

<type 'int'>
<type 'long'>

Python 2 Maximum and Minimum Values

import sys
print(sys.maxint)  # Max Integer value
print(-sys.maxint - 1)  # Min Integer value

2147483647
-2147483648

Python 3 Integer Behavior

In Python 3, sys.maxint was removed and replaced with sys.maxsize. All integers have unlimited precision ?

import sys
print(type(sys.maxsize))
print(type(sys.maxsize + 1))

<class 'int'>
<class 'int'>

Both values remain as int type, demonstrating that Python 3 merged int and long types.

Python 3 Maximum Size

import sys
print(sys.maxsize)

9223372036854775807

Demonstrating Unlimited Precision

Python 3 can handle arbitrarily large integers limited only by available memory ?

# Very large integer calculation
large_number = 2 ** 1000
print(f"2^1000 has {len(str(large_number))} digits")
print(f"Type: {type(large_number)}")

2^1000 has 302 digits
Type: <class 'int'>

System Information Comparison

Float and Integer Information

You can inspect system limits for different numeric types ?

import sys

print("Float information:")
print(f"  Max: {sys.float_info.max}")
print(f"  Min: {sys.float_info.min}")

print(f"\nInteger information:")
print(f"  Max size: {sys.maxsize}")
print(f"  Int info: {sys.int_info}")

Float information:
  Max: 1.7976931348623157e+308
  Min: 2.2250738585072014e-308

Integer information:
  Max size: 9223372036854775807
  Int info: sys.int_info(bits_per_digit=30, sizeof_digit=4)

Conclusion

Python 3 integers have unlimited precision bounded only by available memory, unlike Python 2's fixed-size integers. Use sys.maxsize to get the maximum value a Py_ssize_t can hold, which represents the practical limit for container sizes.