Vector Addition Calculator – Resultant, Magnitude, and Direction
Vector addition is one of the most fundamental operations in physics, engineering, navigation, and computer graphics — it combines two or more vector quantities, such as forces, velocities, or displacements, into a single resultant vector. This calculator adds (or subtracts) vectors in 2D or 3D, supports combining up to six vectors at once, and reports the resultant's components, magnitude, and direction angle alongside a step-by-step breakdown.
The Component Method of Vector Addition
Vectors are added component-wise: corresponding components are simply summed together.
- 2D:
A + B = (Ax + Bx, Ay + By) - 3D:
A + B = (Ax + Bx, Ay + By, Az + Bz)
For example, if A = (3, 4) and B = (1, 2), then A + B = (4, 6). This generalizes cleanly to more than two vectors: for any set of vectors V1, V2, …, Vn, the resultant is R = ΣVᵢ, the component-wise sum of every vector in the set — useful for superposition problems like summing several forces acting on the same object.
The Triangle and Parallelogram Rules
Geometrically, component addition is equivalent to the triangle rule: draw vector A, then draw vector B starting from the tip of A, and the resultant is the arrow from the origin to the final tip. The parallelogram ruleis an equivalent construction for two vectors — draw A and B from a shared origin, complete the parallelogram they form, and the resultant is the diagonal from that origin. This calculator's diagram illustrates the triangle rule directly, chaining each vector tip-to-tail before overlaying the resultant.
Vector Subtraction
Subtracting one vector from another, A − B, is mathematically the same as adding the negation of B: A − B = A + (−B), where every component of B is flipped in sign. For example, with A = (5, 3) and B = (2, 7), A − B = (3, −4). Vector subtraction is especially useful for finding the vector that points from one location to another, or the relative velocity between two moving objects.
Magnitude and Direction of the Resultant
Once the resultant's components are known, its length (magnitude) follows from the Pythagorean theorem: |R| = √(Rx² + Ry² [+ Rz²]). In 2D, the direction angle relative to the positive x-axis is θ = atan2(Ry, Rx), which the calculator reports in both degrees and radians, along with the equivalent polar form |R| ∠ θ.
Polar Form Input
In 2D mode, vectors can also be entered as a magnitude and angle instead of x/y components. The calculator converts each polar vector to Cartesian form using x = m·cos θ and y = m·sin θ before adding, then reports the resultant in both component and polar form — handy when your source data (like a compass bearing or a velocity reading) is naturally given as a magnitude and angle rather than x/y coordinates.
Equilibrium and the Zero Vector
Real-World Applications
- Physics — net force: Combine multiple force vectors acting on an object to find the single net force that determines its acceleration.
- Navigation:Add a vessel's velocity vector to a current or wind vector to find the resulting ground velocity and heading.
- Computer graphics: Sum displacement or motion vectors to update object positions frame by frame.
- Engineering statics: Check whether a structure is in equilibrium by verifying that all applied force vectors sum to zero.
Using This Calculator
Choose 2D or 3Dmode, enter each vector's components (or switch to polar input in 2D), and toggle between Add and Subtract for two-vector calculations. Use Add Another Vector to combine up to six vectors at once, expand the Step-by-Step Calculation panel to see the substituted component sums, and use the copy or share buttons to save your results or send a pre-filled link to a colleague or classmate.