Python 2 to 3 Converter
Automatically migrate legacy version 2 code to modern version 3 syntax.
Why use this tool?
Use the 2to3 Converter to instantly modernize legacy Python 2 scripts to Python 3 syntax. It automatically handles the tedious structural updates required to keep old codebases secure and operational.
print 'Hello World'
# Python 2 specific dict iteration
my_dict = {'a': 1, 'b': 2}
for k, v in my_dict.iteritems():
print k, vAbout Python 2 to 3 Converter
The Python 2 to 3 Converter automatically translates legacy Python 2 source into modern Python 3 syntax, applying the same transformations as the standard library's 2to3 tool. Python 2 reached end-of-life on January 1, 2020 and no longer receives security patches, so any remaining Python 2 code is both a security liability and a compatibility problem as libraries and operating systems drop support for it.
The converter handles the mechanical syntax changes that make up the bulk of a migration: turning the print statement into the print() function, updating exception syntax (except Exception, e becomes except Exception as e), fixing integer division semantics, adjusting dictionary methods like .has_key() and the behavior of keys()/items(), and renaming standard-library modules that moved between versions (for example urllib2 and StringIO).
What it can't do is reason about your program's intent, and the most important example is text vs. bytes. Python 2 blurred the line between str and unicode; Python 3 makes a strict distinction between str (text) and bytes (binary). Code that relied on the old, loose behavior often needs a human to decide what should be text and what should be bytes — 2to3 can flag the area but can't always choose correctly for you.
Because of that, treat the converted output as a strong first pass rather than a finished port. The right workflow is to convert, run your test suite against the Python 3 result, and manually review anything touching file encodings, network payloads, or binary data. A codebase with good test coverage can usually be migrated quickly; one without tests needs more careful manual verification.
Everything runs in your browser — paste the old script, get the Python 3 version back instantly, with nothing to install and no code leaving your machine.
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