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How to use this calculator
Fill in any three of the five values (s, u, v, a, t) and leave the other two empty. The calculator picks the right equations of motion, finds both missing values, and shows the working. Use negative numbers for slowing down.
How it's calculated
The equations of motion (SUVAT) for constant acceleration: v = u + at, s = ut + ½at², v² = u² + 2as, s = ½(u + v)t and s = vt − ½at². s is displacement, u initial velocity, v final velocity, a acceleration and t time.
Worked example
A car starts from rest (u = 0) and accelerates at 2 m/s² for 10 s. Then v = 0 + 2 × 10 = 20 m/s and s = 0 + ½ × 2 × 10² = 100 m.
Frequently asked questions
Why do I sometimes get two answers?
Equations with a square (like s = ut + ½at²) can have two solutions. For time, the negative one is left out. For velocity, the ± shows direction.
Which units should I use?
Metres, seconds, m/s and m/s². Keep them consistent.
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Last updated October 2026. Results are for learning and guidance; always check important work. Calculations run in your browser and are not stored.