Mathematics · Linear Algebra

Angle Between Vectors Calculator

Find the angle between two three-dimensional vectors using their dot product.

Runs locally
Your numbers

Inputs and results stay in this browser. Change one value at a time to explore the relationship.

Your inputCalculatedPassed forward in chains
Angle in degrees90
Angle in radians1.570796
Cosine of angle0

Calculation steps

  1. Dot product = 0; magnitudes = 1 and 1.
  2. cos θ = 0 ÷ (1×1) = 0.
  3. θ = arccos(0) = 90°.

Problem → model → reason → result

What problem does this model solve?

Find the angle between two three-dimensional vectors using their dot product.

Why does the model apply?

Normalising the dot product removes vector length, leaving the cosine of their directional separation.

What assumptions does it make?

Vector components share one coordinate basis, matrix entries are entered in the displayed positions, and the selected finite-dimensional model represents the transformation being studied.

Formula

θ = arccos[(a·b)/(‖a‖‖b‖)]

Calculation and working

The calculator above substitutes your inputs into the model and leaves the calculation steps visible so the answer can be checked rather than merely accepted.

What does the result mean?

The result answers the stated problem in the units implied by your inputs. Read its sign, size and units together, then compare it with the original values before drawing a conclusion.

Worked example

Perpendicular vectors (1,0,0) and (0,1,0) have dot product 0 and angle 90°.

Common mistake

The angle is undefined if either vector has zero magnitude.

When does this model not apply?

Small real vectors and 2×2 matrices introduce the concepts but do not cover complex vector spaces, higher dimensions, numerical conditioning or every decomposition.

How to learn with this calculator

Begin with the worked example, then change one value while keeping the others fixed. Compare the new result and calculation steps to identify which part of the formula changed.

Clear answers

Frequently asked questions

What does the Angle between vectors do?

Find the angle between two three-dimensional vectors using their dot product.

How does the Angle between vectors work?

The calculator applies θ = arccos[(a·b)/(‖a‖‖b‖)]. Normalising the dot product removes vector length, leaving the cosine of their directional separation.

What can I learn from the Angle between vectors?

It connects the mathematical rule to your chosen numbers and shows each calculation step. Change one input at a time to see how the result responds.

Does MW SysArc receive or store what I enter?

No. The calculation runs locally in your browser. MW SysArc does not receive or store your calculation inputs.

How should I use the result?

Use the steps to understand the method, then verify important school or professional work using the notation and rounding rules required in your setting.

Last reviewed 2026-07-14. Calculations tested 2026-07-14.