Almost every vacuum lifter, often called a gripster in the trade, advertises a figure between 200 and 300 kg; the median across all 519 models in the database is 200 kg. This guide explains what that rating means physically, when it applies and how much you should ask of a vacuum lifter in everyday use. With the density table, you can also calculate the weight of any tile, stone slab or glass pane in a few seconds.
What the kg rating describes
The load capacity on the data sheet is the force required to pull the vacuum lifter vertically off a smooth, clean, flat surface. It is generated by the vacuum under the suction plate: on the outside, the ambient air presses with about 1 bar, while the pressure inside is reduced. The pressure difference times the area gives the holding force.
A worked example: a suction pad with an effective diameter of 20 cm has an area of about 314 cm². 1 bar equals 10 newtons per square centimeter. At 0.8 bar of vacuum, 8 newtons therefore press on every square centimeter, a total of about 2,500 newtons. That corresponds to a good 250 kg.
Two things follow from this. First, the holding force depends directly on the area: a pad twice the size holds twice as much at the same vacuum. Second, the vacuum can never exceed atmospheric pressure. More than about 10 newtons per square centimeter is physically impossible, no matter how powerful the pump.
Why almost all vacuum grippers state 200 to 300 kg
The calculation explains the clustering. An 8-inch pad, roughly 200 mm in outer diameter, delivers exactly this order of magnitude at a good vacuum. For significantly more, you need a larger suction area. The distribution in the database reflects this:
| Load capacity class | Models | Median price |
|---|---|---|
| Up to 100 kg | 50 | €74 |
| Over 100 to 200 kg | 156 | €70 |
| Over 200 to 300 kg | 195 | €57 |
| Over 300 kg | 5 | €46 |
At least two thirds of all models with a stated load capacity fall between 200 and 300 kg, because in the over 100 to 200 kg class, at least half of the models state exactly 200 kg. The 5 models over 300 kg are rated at 400 to 500 kg. Without exception, they are oval units with a larger suction area, four of them with a vibration function.
What stands out is that more kilos do not cost more. Units in the over 200 to 300 kg class have a median price of €57, units up to 100 kg €74. The small vacuum grippers are often specialist units: 44% have a foam seal, 40% a narrow suction plate.
Vertical pull and shear load
What matters in practice is the direction in which the load pulls on the vacuum lifter.
Vertical pull: The panel lies flat and you lift it straight up. The force acts perpendicular to the seal. The data sheet rating applies only to this case.
Shear load: The panel is carried on edge or placed against a wall. The load now pulls parallel to the seal. The vacuum does press the seal onto the surface, but the panel is held by the friction between rubber and surface. On smooth, dry surfaces this friction reaches only a fraction of the contact force, and even less on damp, dusty or glazed surfaces. The actual holding force is then often half the rated value or lower.
Tilting and swiveling: When you raise a flat-lying panel, leverage comes into play as well. The load tries to peel the seal away on one side. This is the most critical moment when working with vacuum lifters.
| Load case | What holds the panel | Planning value relative to rated load |
|---|---|---|
| Lying flat, lifted vertically | Vacuum directly | 50% at most |
| Carried on edge or placed against a wall | Friction of the seal | 25% at most |
| Raising, tilting, swiveling | Vacuum against leverage | 25% at most, move slowly |
For a vacuum lifter with a rated load of 200 kg, that means about 100 kg when lifting flat and about 50 kg when carrying on edge.
Safety factor: how much reserve makes sense
For vacuum lifting devices in professional lifting equipment engineering, a safety factor of at least 2 between holding force and permissible load is standard. Some data sheets in the database state this directly, for example with a load capacity of 240 kg and a recommended working load of 120 kg.
The reserve covers factors that cannot be avoided in everyday use:
- Dynamics: A jolt while walking or a brief catch can multiply the force on the vacuum gripper for a moment.
- Wear: An aged or dirty sealing lip holds the vacuum less well.
- Battery level: With a weak battery, the pump builds up vacuum more slowly and to a lower level.
- Temperature: Cold rubber hardens and seals less well.
Often the bottleneck is not the vacuum gripper anyway, but the person. For loads that one person carries regularly, around 25 kg is considered a sensible upper limit. Above that, the panel needs two people and two vacuum lifters.
How surface and seal change the load capacity
The rated value assumes an ideal surface: glass, glazed tiles, polished stone. On textured, porous or curved surfaces, the seal draws in air, the vacuum drops and the pump has to work again. Typical problem cases are tiles with a relief surface, slip-resistant flooring, flamed or bush-hammered natural stone, exposed concrete and open-grain wood.
The seal determines how well a unit copes with this. Vacuum lifters with a rubber seal state a median of 240 kg, models with a foam seal 140 kg. Foam compensates for unevenness and holds where rubber would not build up any vacuum at all, but it does not reach the same figures on smooth surfaces. You will find the comparison of the two seal types under Rubber vs. foam, and an overview by material in the surface guide.
Regardless of the seal: dust, adhesive residue and cutting slurry under the sealing lip cost holding force. Never place the suction plate over joints, bevels, holes or the edge of the panel.
Calculating the weight of a tile or panel
A simple formula gives you the weight of any panel:
Weight in kg = area in m² × thickness in mm × density in g/cm³
The formula works because one square meter at 1 mm thickness equals exactly one liter.
| Material | Density in g/cm³ | Weight per m² at 10 mm |
|---|---|---|
| Ceramic (earthenware, wall tile) | 1.9 to 2.1 | approx. 20 kg |
| Porcelain stoneware | 2.3 to 2.5 | approx. 24 kg |
| Granite | 2.6 to 2.8 | approx. 27 kg |
| Marble | 2.6 to 2.8 | approx. 27 kg |
| Glass | 2.5 | 25 kg |
Worked examples
| Panel | Calculation | Weight |
|---|---|---|
| Porcelain stoneware 60 × 120 cm, 10 mm | 0.72 m² × 10 × 2.4 | approx. 17 kg |
| Porcelain stoneware 120 × 120 cm, 10 mm | 1.44 m² × 10 × 2.4 | approx. 35 kg |
| Porcelain stoneware 120 × 260 cm, 6 mm | 3.12 m² × 6 × 2.4 | approx. 45 kg |
| Marble 60 × 60 cm, 20 mm | 0.36 m² × 20 × 2.7 | approx. 19 kg |
| Glass pane 100 × 200 cm, 8 mm | 2.0 m² × 8 × 2.5 | 40 kg |
| Granite countertop 60 × 300 cm, 30 mm | 1.8 m² × 30 × 2.7 | approx. 146 kg |
From weight to number of vacuum lifters
Divide the weight by the planning value per unit and round up. The 146 kg granite countertop is carried on edge. With vacuum lifters rated at 200 kg and a planning value of 25%, i.e. 50 kg, that makes three units. At the same time, the slab needs four to six people: only with six helpers does each one carry just about 24 kg. Long stone slabs are also prone to breaking; the guide Moving natural stone and countertops has advice on this.
Frequently asked questions
How much can I actually lift with a 200 kg vacuum gripper?
When lifting a flat-lying panel vertically, plan for no more than half, i.e. about 100 kg. If the panel is carried on edge, it is held only by the friction of the seal. In that case, about 50 kg is a sensible planning value. In both cases, this assumes a smooth, clean surface and a vacuum display in the green zone.
Does the load capacity also apply to panels carried on edge?
No. The rating refers to vertical pull from a flat-lying surface. With panels carried on edge, the load acts parallel to the seal and the panel is held by friction. The actual holding force is then often half the rated value or lower, and even less on damp or dusty surfaces.
Why does my gripster hold less well on some tiles?
Usually it comes down to the surface. Textured, slip-resistant or slightly porous tiles let air in under the sealing lip, and the vacuum drops. Dust, adhesive residue or an aged seal also cost holding force. Vacuum grippers with a foam seal are better suited to rough surfaces, although they state a median of only 140 kg instead of 240 kg.