Gas Struts (N-Rating in Newtons) — How to Calculate & Understand Lifting Force

February 19, 2026

A gas strut is a hydropneumatic adjustment fitting designed to support the opening and closing movement of furniture flaps. The force of the strut is specified as an N-rating (Newtons), which must be precisely matched to the flap weight and flap height so the door remains safely open and does not slam shut unexpectedly.

What Exactly Is a Gas Strut?

Inside a gas strut damper is a sealed cylinder filled with nitrogen under high pressure. A piston rod travels within this cylinder. When opening the cabinet flap, the gas pushes the piston outwards, assisting the lifting motion. Acting like an invisible, muscular arm, the strut supports the weight of the front and holds it in the desired position. When closing, the gas is compressed again by the pressure applied to the flap, which simultaneously creates a braking, controlled damping effect. These components belong to the broader category of flap fittings.

Understanding and Calculating Lifting Force in Newtons (N)

The most crucial technical specification when choosing a fitting is the extension force, measured in Newtons (N). An N-rating that is too low will cause the flap to drop shut on its own. A rating that is too high means the flap requires significant effort to close or may even tear the hinges out of the carcase.

As a rough rule of thumb for calculation: 1 kg of flap weight (including the handle) corresponds to approximately 10 N. For a flap weighing 2.5 kg, a theoretical holding force of 25 N is required. However, because cabinet flaps operate via leverage, the flap height plays a decisive role in the calculation. Manufacturers supply specific tables for this purpose. On wide flaps, two struts (left and right) are always installed to prevent the front from warping. The total force required is then divided equally between both dampers.

Types and Variants

Different designs are used depending on the piece of furniture and the weight of the front:

Standard Dampers: For light to medium-weight MDF or chipboard fronts in wall cabinets.
Heavy-Duty Versions: A gas strut for heavy flaps is engineered for solid timber fronts or large framed doors.
Branded Systems: Recognised industry standards like the LIFT-O-MAT provide precisely calibrated damping curves.
Mechanical Alternatives: When pneumatic assistance is not required, classic flap stays are used, operating purely via friction.

To match internal cabinet aesthetics, dampers are available in various finishes. Common choices include the silver gas strut for neutral cabinets, the black gas strut for dark decors, and the white gas strut for light-coloured kitchen cabinets.

Dimensions, Standards, and Typical Values

When installing or replacing worn struts, two length measurements must be observed:

Overall Length: The distance from ball joint to ball joint when fully extended (typically between 240 mm and 270 mm).
Stroke: The maximum travel distance of the piston rod (often 90 mm).

Force ratings are standardised across the furniture fittings industry. Common values are 50 N, 60 N, 80 N, 100 N, 120 N, and 150 N. Specialist heavy-duty versions range from 200 N to 350 N.

Application & Installation

Gas struts are primarily fitted in kitchen wall units, bathroom cabinets, and living room sideboards with lift-up flaps. Installation is carried out using mounting brackets screwed to the carcase interior and the flap. The strut is then simply clipped onto the ball studs. A similar pneumatic principle, though for vertical pull-down movement, is used by wardrobe rail lifts in wardrobes.