Gas Spring Calculator

Gas Spring Force Calculator

Determine the required Newton (N) force for your lid or hatch struts.

1 Spring 2 Springs

Recommended Force Per Spring:

0 N

How Gas Spring Force Calculation Works

Choosing the correct gas spring (also known as a gas strut) is critical for both safety and functionality. A spring that is too weak won't hold the lid open, while one that is too strong can damage the hinges or make the lid impossible to close.

The Basic Physics Formula

The force required is based on the moment (torque) around the hinge. The formula used by this calculator is:

F = ((W * 9.81) * CG) / (M * N) * 1.15
  • W (Weight): Total weight of the lid in kilograms.
  • 9.81: Gravity constant to convert mass (kg) to force (Newtons).
  • CG (Center of Gravity): Distance from the hinge to the center of weight (usually the midpoint of the lid).
  • M (Mounting Distance): Distance from the hinge to the point where the gas spring is attached to the lid.
  • N (Number of Springs): How many struts will support the load.
  • 1.15: A 15% safety factor to account for friction and gas pressure fluctuations.

Standard Example Calculation

Suppose you have a wooden storage box lid weighing 10 kg. The lid is 600mm long, so the Center of Gravity is 300mm from the hinge. You plan to mount the gas struts 200mm from the hinge using 2 springs.

  • Force = ((10kg * 9.81) * 300mm) / (200mm * 2) * 1.15
  • Force = (98.1 * 300) / 400 * 1.15
  • Force = 29430 / 400 * 1.15
  • Result = ~84.6 Newtons per spring

Pro Tips for Installation

1. Mounting Direction: Always mount gas springs "rod down" (piston facing down) in the open position to ensure internal oil lubricates the seals.

2. Temperature Effects: Gas springs lose approximately 3% of their force for every 10°C drop in temperature. If you use your equipment in cold climates, choose a slightly higher Newton rating.

3. Hinge Strength: Adding gas springs puts significantly more stress on hinges. Ensure your hinges are bolted securely to the frame.

function calculateGasForce() { var weight = parseFloat(document.getElementById('lidWeight').value); var cg = parseFloat(document.getElementById('distCG').value); var mount = parseFloat(document.getElementById('mountDist').value); var springs = parseInt(document.getElementById('numSprings').value); var resultDiv = document.getElementById('resultArea'); var display = document.getElementById('forceResult'); var msg = document.getElementById('totalForceMsg'); if (isNaN(weight) || isNaN(cg) || isNaN(mount) || weight <= 0 || cg <= 0 || mount <= 0) { alert("Please enter valid positive numbers for weight, center of gravity, and mounting distance."); resultDiv.style.display = "none"; return; } // Convert kg to Newtons (Weight * 9.81) var weightInNewtons = weight * 9.81; // Torque Calculation: (WeightN * CG Distance) / (Mounting Distance * Number of Springs) // Applying a 15% safety factor (1.15) for friction and safety var requiredForce = (weightInNewtons * cg) / (mount * springs) * 1.15; // Standard Gas Springs come in increments (usually 50N or 100N) // We round to the nearest whole number for display var finalN = Math.round(requiredForce); display.innerHTML = finalN + " N"; var totalN = finalN * springs; msg.innerHTML = "Total combined lift force: " + totalN + " Newtons across " + springs + " spring(s)."; resultDiv.style.display = "block"; resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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