Logical Equivalence Calculator with Steps

Enter two formulas and compare every row. See clear steps for each truth value now. Export tables for notes, homework, and proof checks quickly.

Calculator Input

NOT: !, ~, ¬, not
AND: &, ∧, and
OR: |, ∨, or
XOR: ^, ⊕, xor
IMPLIES: ->, =>, implies
IFF: <->, <=>, iff

Use true, false, 1, or 0. Variables may use letters, digits, and underscores.

Formula Used

Two formulas A and B are logically equivalent when A ↔ B is true for every possible assignment of their variables.

Equivalence test: A ≡ B if and only if eval(A, row) = eval(B, row) for all truth table rows.

Truth table size: rows = 2n, where n is the number of distinct variables.

Implication: p → q is false only when p is true and q is false. In other rows, it is true.

Biconditional: p ↔ q is true when p and q have the same truth value.

How to Use This Calculator

  1. Enter the first logic statement in the first box.
  2. Enter the second logic statement in the second box.
  3. Set a variable order if you want a custom table order.
  4. Choose the truth value format for the result table.
  5. Press the calculate button.
  6. Review the verdict, truth table, and row steps.
  7. Use CSV or PDF download buttons to save the work.

Example Data Table

This example compares p -> q with !p | q.

p q p -> q !p | q Same
F F T T Yes
F T T T Yes
T F F F Yes
T T T T Yes

Understanding Logical Equivalence

Logical equivalence means two statements always share the same truth value. They may look different. They still say the same thing in every possible case. This calculator checks that idea by building a complete truth table.

Why Truth Tables Matter

A truth table lists every possible assignment for the variables used in both formulas. For each row, the tool evaluates the left expression and the right expression. If both final columns match on all rows, the formulas are equivalent. If one row differs, they are not equivalent.

What The Tool Solves

The calculator accepts common symbols and plain text operators. You may type not, and, or, xor, implies, and biconditional forms. It also supports compact symbols like !, &, |, ->, and <->. Parentheses control grouping. This makes the tool useful for class work, digital logic, and proof checking.

Step Based Evaluation

Each row includes a short step trail. The trail shows variable values first. Then it shows how inner parts are evaluated. Finally, it compares both complete formulas. These steps help you find exactly where two expressions agree or fail.

Useful Study Features

The result panel gives the verdict first, so the answer is easy to see. The full table follows below. You can also download the table as a CSV file. A simple PDF report is available for notes or submission. These exports help keep work organized.

Good Formula Habits

Use clear variable names. Keep parentheses around important groups. Write implications with ->. Write biconditionals with <->. Check one idea at a time when a formula becomes long. Smaller formulas are easier to debug.

Practical Examples

A classic equivalence is p -> q and !p | q. Another common law is !(p & q) and !p | !q. These are not just symbolic tricks. They explain how conditions, switches, rules, and permissions can be rewritten safely.

Final Note

Logical equivalence is a strict test. Matching most rows is not enough. The formulas must match every row. Use the steps and table together for the clearest proof. Review exported results before sharing them. Small typing errors can change a whole proof. Try replacing rare symbols with text operators when needed. Save examples that helped you understand a rule, especially during exams too.

FAQs

What is logical equivalence?

Logical equivalence means two formulas have the same final truth value for every possible variable assignment. If even one truth table row differs, the formulas are not equivalent.

Which operators can I enter?

You can use not, and, or, xor, implication, and biconditional operators. The calculator accepts both text forms and symbols such as !, &, |, ->, and <->.

Does the calculator show steps?

Yes. Each truth table row includes a step trail. It shows variable values, subexpression results, and the final comparison for both entered formulas.

Can I change the variable order?

Yes. Enter variables in the order field, separated by commas or spaces. Missing variables are added automatically after your chosen order.

What does a mismatch row mean?

A mismatch row means the two formulas produce different final truth values under that assignment. One mismatch is enough to prove they are not equivalent.

Can I download the result?

Yes. After calculation, use the CSV button for spreadsheet work. Use the PDF button for a printable report with table values and steps.

How many variables are supported?

The calculator allows up to eight distinct variables per run. This keeps truth tables readable and prevents very large table output.

What is a tautology?

A tautology is a formula that is true in every truth table row. The calculator labels each expression as tautology, contradiction, or contingency.

Related Calculators

Paver Sand Bedding Calculator (depth-based)Paver Edge Restraint Length & Cost CalculatorPaver Sealer Quantity & Cost CalculatorExcavation Hauling Loads Calculator (truck loads)Soil Disposal Fee CalculatorSite Leveling Cost CalculatorCompaction Passes Time & Cost CalculatorPlate Compactor Rental Cost CalculatorGravel Volume Calculator (yards/tons)Gravel Weight Calculator (by material type)

Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.