One panel, four routes to a.
Pick a mode below — it recalculates live as you type, converts any unit you throw at it, and every result explains itself.
Speed when timing starts — 0 for anything starting from rest.
Speed when timing ends — the gap between the two is what acceleration measures. Units can differ from vi.
How long the change takes — must be more than zero.
The big answer follows your choice — g-force is always shown too.
Speed when timing starts — 0 from a standing start.
Total ground covered during the interval — works while speeding up or slowing down.
Length of the interval — must be more than zero.
The total push or pull along the direction of motion — negative means the other way.
How much matter is being pushed — not the same as weight.
Type any acceleration and see it in every unit at once — including g-force.
Four steps, ten seconds.
No setup and nothing to configure — the calculator works the way you already think.
Pick a mode
Four tabs: velocity change, distance & time, force & mass, or the unit converter. Start with whatever you already know.
Type your values
Enter numbers in the units you have — km/h, mph, metres, feet, minutes or hours. Everything converts to SI behind the scenes.
Choose the output unit
m/s², ft/s², km/h per second, mph per second or g-force — the big answer follows your choice, and g-force is always shown.
Verify, then copy
Every result includes the formula with your numbers substituted in. One click copies the whole result set anywhere you need it.
Three ways to find a.
Every mode in the calculator is one of these — pick the route that matches what you know.
From velocity & time
The definition of acceleration: how much velocity changes each second. A car going 0 → 27.78 m/s in 8 s gains 3.47 m/s² — about 0.35 g.
From distance & time
Know the ground covered instead of the final speed? From rest this collapses to a = 2d ÷ t² — 400 m in 20 s means 2 m/s².
From force & mass
Newton's second law. The same 3000 N shove moves a 1200 kg car at 2.5 m/s² but a 30 kg bike at 100 m/s² — mass is the price of inertia.
Acceleration, answered.
The questions people actually type into Google — answered plainly, with the numbers to back them up.
What is acceleration?+
Acceleration is the rate at which velocity changes over time — speeding up, slowing down or turning all count. It is measured in metres per second squared (m/s²): a car accelerating at 3 m/s² gains 3 m/s of speed every second.
How do I calculate acceleration?+
Use a = (v_f − v_i) ÷ t — subtract the starting velocity from the final velocity, then divide by the time taken. A car going from 0 to 100 km/h (27.78 m/s) in 8 s accelerates at 27.78 ÷ 8 ≈ 3.47 m/s². Mode 01 above also shows distance covered, average speed and g-force.
How do I find acceleration from distance and time?+
With constant acceleration, a = 2(d − v_i·t) ÷ t². From rest it simplifies to a = 2d ÷ t² — a sprinter covering 100 m in 9.58 s from a standing start averages about 2.18 m/s². Mode 02 does this and also returns the final velocity.
How do I calculate acceleration from force and mass?+
Newton's second law: a = F ÷ m. A net force of 3000 N on a 1200 kg car gives 3000 ÷ 1200 = 2.5 m/s². Keep the units consistent — mode 03 accepts N, kN, lbf and kgf with kg, g, lb or tonnes and converts automatically.
What units is acceleration measured in?+
The SI unit is m/s². You will also meet ft/s² (1 ft/s² = 0.3048 m/s²), km/h per second (1 km/h·s ≈ 0.2778 m/s²), mph per second, and g-force where 1 g = 9.80665 m/s². Mode 04 converts between all of them instantly.
What does 1 g of acceleration mean?+
1 g = 9.80665 m/s² — the acceleration of a freely falling object near Earth's surface, and the pull that gives you your normal weight. For comparison: a hard-braking car reaches about 0.8–1 g, astronauts at launch about 3 g, and fighter jets up to 9 g.
Can acceleration be negative?+
Yes. Negative acceleration means velocity decreases in your chosen positive direction — deceleration, like braking from 100 km/h to 0 in 5 s (−5.56 m/s²). In mode 02 a negative final velocity simply means the object reversed direction during the interval.
Is this calculator free, and is my data sent anywhere?+
It is completely free and runs entirely in your browser — nothing you type is uploaded, logged, or sent to a server. No account, no sign-up, no limits.