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Dot Product Calculator

a·b in 2 to 10 dimensions with the term-by-term sum, both magnitudes as exact radicals, the angle in degrees and radians, the projections, and a figure. Parallel and orthogonal are decided in exact fractions, so (1,1,1)·(2,2,2) returns 0°, not NaN.

Related tools

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Open Dot Product Calculator and you get an answer straight away, with no account to create. It sits under Matrices & vectors in our catalogue, alongside Cross Product Calculator and Tensor Product Calculator (Kronecker product A ⊗ B).

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What is Dot Product Calculator?

a·b in 2 to 10 dimensions with the term-by-term sum, both magnitudes as exact radicals, the angle in degrees and radians, the projections, and a figure. Parallel and orthogonal are decided in exact fractions, so (1,1,1)·(2,2,2) returns 0°, not NaN.

When would I actually use this?

Checking a decomposition done by hand, solving a linear system, and finding the eigenvalues that describe how a transformation stretches space.

What is the most common mistake?

Inverting a matrix to solve a system. Elimination or a factorisation is both faster and far more stable numerically; an explicit inverse amplifies rounding error, especially when the matrix is close to singular.

How is Dot Product Calculator different from Cross Product Calculator?

They sit next to each other but answer different questions: Cross Product Calculator is the one to open when you need it to a × b in 3D with the determinant expansion shown, the magnitude |a||b|sin θ, the parallelogram and triangle areas, the unit normal and the right-hand rule. Pick whichever matches what you're starting from — both are free.

Is there a tool for the next step?

Tensor Product Calculator (Kronecker product A ⊗ B) is the closest one after this: The Kronecker product of two matrices of any shape, block by block, in exact fractions or 6 / 10 significant digits — with the (m·p) × (n·q) size rule and the identities on rank, transpose and determinant.

What else is worth having open alongside it?

Product notation calculator (pi notation) and Angle Between Two Vectors Calculator — they come up in the same task often enough to be worth a second tab.

Where do the figures come from?

The decompositions follow their textbook definitions with partial pivoting where it applies. Results are exact for small integer matrices and subject to floating-point rounding otherwise.

Further reading

All guides →
ExplainerThe Flat Pattern of a Cone Is a Sector, Not a CircleRoll a 50 mm cone 80 mm tall and its pattern is a 190.8° slice of a 94 mm circle. Flatten a nearly cylindrical lampshade and the pattern radius runs to 839 mm — the shallower the taper, the further away the apex.ExplainerA 1 % Drop Rate Does Not Mean One Hundred RunsAt 1 %, a hundred attempts give you 63.4 % — not certainty. Ninety per cent takes 230 attempts and ninety-nine takes 459, and more than a third of players are still empty-handed at a hundred.ExplainerFibonacci and the Golden RatioThe Fibonacci sequence adds each pair of terms to make the next; the ratio of neighboring terms homes in on the golden ratio φ ≈ 1.618. See how, and where the pattern turns up.ExplainerWhat Is a Z-Score? Standard Deviations Above the MeanA z-score is z = (x − μ) / σ — how many standard deviations a value sits from the mean. Learn how to compute it, read the standard normal curve, and turn it into a percentile.How-toHow to Find the Distance Between Two PointsUse the distance formula d = √((x₂−x₁)² + (y₂−y₁)²) to measure the straight-line distance between two points on a plane, with a worked example and the midpoint too.How-toHow to Calculate the Slope of a Line: Rise Over RunFind the slope of a line from two points with m = (y₂ − y₁) / (x₂ − x₁), and read what a positive, negative, zero, or undefined slope tells you.