Linear Algebra

Matrix Rank

The rank of a matrix is the number of linearly independent rows — equivalently, the number of pivots in its row echelon form. Enter the matrix and the calculator row-reduces it and reports the rank.

Matrix Rank

Number of linearly independent rows — by row reduction.

Try:
Answerrank(A) = 2
  1. Matrix A3×3 [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
  2. MethodRow reduce to echelon form; the rank is the number of non-zero rows (= number of pivots).
  3. Row operationsSwap R1 ↔ R3; R1 → (1/7)·R1; R2 → R2 − (4)·R1; R3 → R3 − (1)·R1; Swap R2 ↔ R3; R2 → (1/0.857143)·R2; R1 → R1 − (1.14286)·R2; R3 → R3 − (0.428571)·R2
  4. Reduced form[[1, 0, -1], [0, 1, 2], [0, 0, 0]]
  5. Pivot columnscolumn 1, column 2
  6. Rankrank(A) = 2
  7. NoteRank < min(rows, cols) = 3: the rows are linearly dependent.

Frequently asked questions

Is row rank the same as column rank?

Yes. For every matrix the number of linearly independent rows equals the number of linearly independent columns — this common value is the rank.

What does full rank mean?

An m×n matrix has full rank when its rank equals min(m, n). A square matrix has full rank exactly when it is invertible.

How does row reduction reveal the rank?

After reducing to row echelon form, each leading 1 corresponds to one independent row. The number of non-zero rows is the rank.