Print Acceleration Time Calculator
A 3D printer move starts at rest, accelerates to a cruise speed, holds it, then decelerates back to a stop, a trapezoidal speed profile. Short moves never reach the set speed and instead form a triangle. This calculator uses constant-acceleration kinematics to find the time to reach the target speed, the distance spent accelerating, and the total time for a move of a given length, including a check for whether the move is long enough to cruise. Enter the target speed, the configured acceleration, and the move distance. The relations are exact physics of uniform acceleration.
Acceleration timing formula
Time to speed = target speed / acceleration
Accel distance = target speed^2 / (2 * acceleration)
If 2 * accel distance <= move distance: trapezoid, peak = target speed
Else triangle: peak = sqrt(acceleration * move distance)
Total time = accel and decel time plus any cruise time
For a short move the printer accelerates over half the distance then decelerates over the other half, so the peak speed is the square root of acceleration times move distance.
Acceleration context
- The relations are exact kinematics of constant acceleration from rest.
- Short moves form a triangle and never reach the set speed.
- Set acceleration in firmware with M204; use your configured value here.
- Higher acceleration often saves more time than higher top speed on detailed prints.
- This model starts and ends at rest; real firmware blends junction speeds between moves.
Acceleration timing: frequently asked questions
How long does it take to reach print speed?
Under constant acceleration, the time to go from rest to a target speed is the speed divided by the acceleration. The distance covered while accelerating is the speed squared divided by twice the acceleration. The same applies in reverse for deceleration.
What is a trapezoidal motion profile?
A move accelerates up to a cruise speed, holds it, then decelerates to a stop, tracing a trapezoid on a speed-versus-time graph. If the move is too short to reach cruise speed, the profile is triangular: it accelerates to a peak and immediately decelerates.
When does a move not reach full speed?
If the move distance is shorter than the distance needed to accelerate and then decelerate, the printer never reaches the set speed. This calculator checks that: it compares the move length to twice the acceleration distance and reports the peak speed actually reached.
What acceleration value should I use?
Use the acceleration set in your firmware or slicer, in millimeters per second squared, set with the M204 command in Marlin. Typical values range widely by machine and frame stiffness, so enter your own configured value.
Why does acceleration matter so much for print time?
Prints are made of many short moves, especially on curved and detailed geometry, and short moves spend most of their time accelerating and decelerating rather than cruising. Higher acceleration shortens those moves, which is often a bigger time saving than raising the top speed.
Official sources
- Marlin firmware documentation: M204 Set Starting Acceleration.
- RepRap project documentation: reprap.org (motion planning reference).
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.