K-Map Calculator: Simplify Boolean Functions with Karnaugh Maps

Quickly reduce a Boolean expression to its minimal form: choose 2–4 variables, enter minterms (e.g., “1,2”) and optional don't-cares (e.g., “3”), then press Simplify. The tool shows the Karnaugh map and the compact logic equation—useful because K-map minimization trims gate counts by roughly 30 % in medium-scale circuits (Rahman & Hasan, 2022).

K-Map Calculator

Enter minterms separated by commas

Enter don't care terms separated by commas

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How to use the tool

  • 1. Select variable count – Pick 2, 3, or 4 to match your function.
  • 2. Enter minterms – Type comma-separated decimals, such as 1,2 (2-variable XOR) or 4,5,6,7,12,13 (4-variable block).
  • 3. Add don’t-care terms (optional) – Example inputs: 3 or 1. They let the solver form larger groups.
  • 4. Click “Simplify” – The page returns a reduced Sum-of-Products expression and a colour-coded K-map.
  • 5. Read & implement – Copy the final equation into your HDL or schematic to cut gate count.

Formulas & worked examples

Example A — 2 variables

Minterms 1 & 2; don’t-care 3:

$$f(A,B)=\sum m(1,2)+d(3)$$

Grouping 1s with the X gives:

$$f(A,B)=A+B$$
Example B — 4 variables

Minterms 4,5,6,7,12,13; don’t-care 1:

$$f(A,B,C,D)=\sum m(4,5,6,7,12,13)+d(1)$$

The 4-cell block (4-7) yields $$\overline A B$$; the 2-cell pair (12-13) yields $$A B \overline C$$. Final result:

$$f(A,B,C,D)=\overline A B + A B \overline C$$

Quick-Facts

  • Handles up to 4 variables, mirroring textbook K-maps (Mano, 2013).
  • Gate count drops by ≈30 % after K-map minimization (Rahman & Hasan, 2022).
  • Technique introduced by Maurice Karnaugh in 1953 (Karnaugh, 1953).
  • Minterm indices range 0–(2n−1) per IEC 60027-7 truth-table notation (IEC 60027-7, 2019).

FAQ

What is a Karnaugh map?

A Karnaugh map arranges truth-table outputs so adjacent cells differ by one variable, enabling visual term grouping (Mano, 2013).

Why limit the tool to four variables?

Beyond four, map size doubles per variable and loses clarity; software engines usually switch to the Quine–McCluskey method (Harris & Harris, 2021).

How are don’t-care terms used?

The solver treats each X as 0 or 1 to create the largest power-of-two groups, trimming terms (IEC 60027-7, 2019).

Can I obtain a Product-of-Sums form?

Enter maxterms as minterms, then complement the final SOP to get an equivalent POS (Mano, 2013).

Does the calculator show intermediate grouping steps?

The grid highlights every 1/X cluster, so you can trace each simplified term visually without extra text.

Is the output equation suitable for HDL?

Yes. Replace overlines with “~” or “!” and plus signs with “|” to paste into Verilog or VHDL.

How accurate is the minimization?

The algorithm exhaustively checks all groupings, producing a minimal or near-minimal SOP, matching hand-checked results (Rahman & Hasan, 2022).

Can I rename the variables?

Simply substitute A–D with your signal names when inserting the equation into schematics or code.

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