Calculate average acceleration, horsepower, mass, or time from three known values, with hp, kW, kg, lb, seconds, and acceleration unit conversions.

Ideal energy model from rest. Average acceleration is final speed ÷ elapsed time; instantaneous acceleration is not constant.

Optional settings

100% assumes no losses. Blank also uses 100%.

HP to Acceleration Formula

The following equation is used to estimate the average acceleration from rest when constant input power and a specified delivered-power fraction are applied for a time t. The default 100% fraction is ideal and lossless. This is final speed divided by time, not constant instantaneous acceleration; the start at rest is an ideal limit. It ignores traction limits, drag, rolling resistance and changing power with speed.

Aavg = v / t = √(2 η Pinput / (m t)).
  • Where Aavg is the average acceleration over the time interval (m/s^2)
  • P is the power delivered to motion (watts). For input power, multiply by the selected delivered-power fraction η; 1 mechanical hp ≈ 745.699872 W.
  • m is the mass (kg)
  • t is the time (s)
Horsepower to Acceleration Conversion Table (Assumes mass = 1500 kg, time = 10 s)
Horsepower (hp) Acceleration (m/s²) Acceleration (ft/s²)
10.3151.035
50.7052.313
100.9973.271
151.2214.007
201.4104.626
251.5775.173
301.7275.666
401.9946.543
502.2307.315
602.4428.013
752.7318.959
1003.15310.345
1503.86212.670
2004.45914.630
2504.98616.357
3005.46217.918
4006.30620.690
5007.05123.132
7508.63528.331
10009.97132.714
Assumes mass = 1500 kg and time = 10 s. Model (constant power from rest): aavg = √(2P/(m t)) with P = HP × 745.699872 W. Unit facts: 1 mechanical hp ≈ 745.699872 W, 1 m/s² = 3.28084 ft/s².

What are the units for HP to Acceleration?

Acceleration is most commonly expressed in SI units of m/s² (meters per second squared), though ft/s² is also common in US customary units.

How to Calculate HP to Acceleration?

Example Problem:

The following example problem outlines the steps and information needed to calculate the HP to Acceleration.

First, determine the total horsepower. In this example, the total horsepower is determined to be 500 (horsepower).

Next, determine the mass. For this problem, the mass is measured to be 5000 (kg).

Next, determine the time. In this case, the time is found to be 10 (s).

Finally, calculate the (average) acceleration using the formula above: 

At 100% delivered power: Aavg = SQRT( (2*HP*745.699872) / (m*t) )

Inserting the values from above and solving the equation with the imputed values gives: 

Aavg = SQRT( (2*500*745.699872) / (5000*10) ) ≈ 3.86 (m/s^2)