Actuator Shock Load Calculator

Estimate deceleration, kinetic energy, and equivalent shock force from moving mass, impact speed, stopping distance, and static load. The result is a preliminary engineering estimate, not a product rating or safety approval.

Calculate shock force

Enter the measured or assumed inputs in one unit system. The calculator converts to SI internally, evaluates the stated model, and displays the result in the selected unit system.

Unit system

Moving mass

Enter moving mass for the modeled condition.

Impact speed

mm_s

Enter impact speed for the modeled condition.

Stopping distance

Enter stopping distance for the modeled condition.

Static load already present

Enter static load already present for the modeled condition.

Idealized stopping deceleration --

Kinetic energy before stop --

Equivalent shock force estimate --

Enter values inside the documented model domain.

Engineering visualizer

Schematic, not to scale. The drawing updates from the production calculation engine and labels the main outputs.

Calculator by FIRGELLI Automations.

Embed this calculator

When embedded on another page, the calculator shows only the working tool. FIRGELLI attribution, the visualizer, and the calculation-error report remain available.

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What the shock number actually means

This is not the same as the steady load you used to pick the actuator. It is the extra slam when a moving mass stops in a short distance. A hatch that eases into a bumper is one number. The same hatch hitting a hard stop is often several times higher.

If the shock result is well above the actuator static rating, lengthen the stop, add a bumper, or slow the last part of the stroke. Do not just buy a bigger rod and keep the same hard stop. Then check the end-limit and duty notes on the product page.

What This Calculator Calculates

What does actuator shock load mean? This quantity describes one specific part of the actuator design problem. It should be read as a model output, not as a complete product selection rule.

When Not To Use This Calculator

When should I not use the actuator shock load model? Do not use this model when the inputs are unknown, the mechanism is outside the stated boundary, or the decision depends on manufacturer ratings, fatigue, shock, compliance, or regulated safety approval.

Engineering model and calculation details

Estimate deceleration, kinetic energy, and equivalent shock force from moving mass, impact speed, stopping distance, and static load.

The page separates the calculator result from product selection. It explains the inputs, limitations, interpretation, and next design checks so the result is not mistaken for a complete actuator rating.

Governing equations

Quantity	Equation	Model meaning
Idealized stopping deceleration	`a = v^2/(2s)`	Calculates idealized stopping deceleration for the stated simplified model.
Kinetic energy before stop	`E = 1/2 m v^2`	Calculates kinetic energy before stop for the stated simplified model.
Equivalent shock force estimate	`F = m a + F_static`	Calculates equivalent shock force estimate for the stated simplified model.

Variables and canonical units

Symbol	Variable	SI unit	Domain
`moving_mass`	Moving mass	kg	finite engineering value in the documented model domain
`impact_speed`	Impact speed	m_s	finite engineering value in the documented model domain
`stopping_distance`	Stopping distance	m	finite engineering value in the documented model domain
`static_load`	Static load already present	N	finite engineering value in the documented model domain
`deceleration`	Idealized stopping deceleration	m_s2	finite result from valid inputs
`kinetic_energy`	Kinetic energy before stop	J	finite result from valid inputs
`equivalent_shock_force`	Equivalent shock force estimate	N	finite result from valid inputs

Assumptions and boundary conditions

Inputs represent one consistent operating condition.
The model uses the simplified boundary stated on the page.
The model begins and ends at the user-defined actuator or mechanism boundary.

Limitations and omitted checks

The result depends on user-entered values and simplified boundary conditions.
The model does not replace FIRGELLI product data, installation review, endurance testing, or a qualified engineering review.
Shock, fatigue, misalignment, mounting strength, and controller behavior may govern before the calculated value.

Worked example

25 kg at 200 mm/s, stop in 4 mm, 400 N already on the rod. a = v²/2s = 5 m/s², E = 0.5 J, F ≈ 525 N. Shorten the stop and F jumps. This is not the static rating.

What this model evaluates

Mode or effect	Status	Disclosure
calculated quantity	evaluated	The named output is evaluated for the stated model.
manufacturer rating	not evaluated	The result is not a manufacturer product rating.
installation detail	not evaluated	Mounting, alignment, shock, fatigue, and environment require separate review.

Common mistakes

Treating a simplified estimate as a manufacturer rating.
Mixing units or entering values measured at a different operating point.
Ignoring mounting, alignment, shock, duty cycle, or controller limitations.
Failing to compare the result with the next logical FIRGELLI design check.

Engineering references

National Institute of Standards and Technology. NIST Guide to the SI. National Institute of Standards and Technology, Accessed 2026. Supports: SI unit definitions and unit-consistent engineering calculation display.. Accessed 2026-07-28. Source.
Barry N. Taylor and Chris E. Kuyatt. Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results. National Institute of Standards and Technology, NIST Technical Note 1297. Supports: Root-sum-square treatment of independent standard uncertainty components.. Accessed 2026-07-28. Source.

Author, validation, and review status

Author: Robbie Dickson

Author profile: Robbie Dickson prepares FIRGELLI actuator education and calculator content for product users and engineering teams.

Engineering model type: Energy-based stopping distance shock-load estimate

Validation: The production JavaScript engine is compared with a separately written Python oracle across known-answer, SI/imperial-equivalent, boundary, invalid-input, and randomized cases.

Questions about this calculator or found an error? Message our engineering team.

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Actuator Shock Load Calculator