Plan drop tests with realistic mass, height, and cushioning. See velocity, energy, and g‑loads instantly. Export a clear report for engineering and quality teams.
These examples assume distance-based stopping and constant deceleration.
| Mass (kg) | Height (m) | Stop distance (mm) | Impact velocity (m/s) | Avg contact force (kN) | Estimated peak (kN, factor 2) |
|---|---|---|---|---|---|
| 1.0 | 0.5 | 10 | 3.13 | 0.50 | 1.00 |
| 2.5 | 1.0 | 15 | 4.43 | 1.89 | 3.78 |
| 5.0 | 1.2 | 20 | 4.85 | 3.05 | 6.10 |
v = √(2gh)a = v² / (2s)a = v / tF_net = m aF_contact = m a + m gF_peak ≈ F_contact × peak_factorThese are simplified engineering estimates. Real impacts depend on cushioning stiffness, orientation, and force-time shape.
The calculator converts drop height into impact velocity using v = √(2gh), then estimates average
deceleration during the stopping phase and converts it to force. Distance input assumes constant deceleration across
the crush stroke. Time input assumes constant deceleration across the measured pulse width.
Common handling drops are often 0.3 m to 1.2 m. At 1.0 m on Earth, impact velocity is about 4.43 m/s. At 0.5 m it is about 3.13 m/s, and at 1.2 m it reaches about 4.85 m/s. Energy grows with mass and height, so heavier products escalate test severity quickly.
For a 2.5 kg package dropped from 1.0 m, impact energy is roughly 24.5 J. With 15 mm stopping distance, average contact force is about 1.9 kN. Increasing distance to 30 mm reduces force close to half, highlighting why cushion stroke matters. In practice, cushioning strokes of roughly 5 mm to 50 mm can shift forces by an order of magnitude.
Time-based input helps when you have a recorded pulse width. For a 1.0 m drop, if stopping time is 8 ms, the estimated net deceleration is about 553 m/s² (≈56 g net). A longer pulse, such as 16 ms, reduces that deceleration by about half.
Net g compares stopping deceleration to gravity. Total g uses contact force divided by weight and includes the weight term during stopping. For severe drops the difference is small, but at low decelerations it can be noticeable.
Real impacts are not flat pulses. Force rises, peaks, then decays. The peak factor estimates a conservative peak as peak ≈ average × factor. Many users start with 1.5 to 3.0 and refine with test traces.
A safety factor multiplies forces for margin. If average contact force is 3.05 kN and safety factor is 1.25, the design force becomes about 3.81 kN. This supports choices like fasteners, foam density, or fixture strength.
Use velocity and energy to compare drop severity, and use force and g-load to compare fragility limits. Increasing stopping distance, adding compliant layers, or spreading contact area usually reduces peak stress. If estimates exceed allowable loads, increase cushioning stroke or reduce drop height.
No. It is an estimate based on constant deceleration and a simplified force model. Real impacts depend on pulse shape, orientation, contact stiffness, and how cushioning compresses.
Use stopping distance when you know crush stroke or foam deflection. Use stopping time when you have sensor data or a measured pulse width. The calculator derives the other value automatically.
Many packaging designs use a few millimeters up to several centimeters of deflection. Softer or thicker cushioning increases distance, usually lowering average force and peak force.
With distance input, deceleration scales roughly with 1/s. Halving stopping distance roughly doubles
deceleration and force, which is why cushion tuning strongly affects results.
If you do not know the pulse shape, start with 2.0 as a conservative placeholder. If you have test traces, choose a factor that matches measured peak divided by measured average.
No. It focuses on the first stopping event. Rebound can create secondary peaks, especially on hard surfaces. If bounce is important, validate with a physical drop test or acceleration data.
Yes, as a screening estimate. Apply an appropriate safety factor and compare peak and average forces to fixture limits. For critical designs, confirm with dynamic testing or instrumented drop trials.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.