Solve Propositional logic problems online!

Welcome to! This system is capable of validating whether or not a given string of text is a Well Formed Formula or not, and give a person a visualization of that formula,and possibly the errors that cause it not to be a well formed formula.

Example of solving a problem animation

An instructor can create logic proof problems by supplying the system with a set of assumptions and a desired conclusion.

A student of logic may then try and solve the proof with a given set of rules.

After creating an account, a student may track their progress in logic and gain confidence by earning achievements.

We hope you can use this site to help yourself or your students better understand propositional logic! In the future, we hope to add support for predicate logic, but we'll need some donations before much more progress is made!

Get in contact with us with any suggestions, problems, or general inquiries. Thanks for visiting!

The system currently supports the following rules:

  • → O
  • → I
  • ↔ I
  • ↔ O
  • ∨ I
  • ∨ O
  • & I
  • & O
  • - O
  • - I
  • Modus Tolens
  • Disjunctive Argument
  • Conjunctive Argument
  • Double Negation
  • Chain Rule
  • Contraposition
  • Demorgan's Law
  • Arrow Rule