How to Read an Excavator Lifting Capacity Chart Without Overloading the Machine
An excavator lifting capacity chart looks like a wall of numbers, and most operators never open it until something goes wrong. That is a shame, because the chart is the cheapest safety device on the machine — it tells you exactly how much you can pick up at any point in the working range, before you find out the hard way.
This is a plain-language walkthrough: what the rows and columns mean, which safety margins are already built in, and the four mistakes that account for most overloading incidents on compact sites.
What the Chart Is Actually Measuring
A lift chart does not describe the machine's strength. It describes the point at which the machine becomes unsafe, with a safety margin already subtracted.
For excavators, the rated lift capacity is defined as the lesser of:
- 75% of the static tipping load — the weight at which the machine would begin to tip over the front of its tracks, reduced by a quarter.
- 87% of the hydraulic lift capacity — the maximum the boom and arm cylinders can raise, reduced by 13%.
Whichever is smaller becomes the published figure. On a compact machine lifting close in, the hydraulic figure usually governs; further out, tipping takes over. That is why the numbers drop steeply as radius increases.
Reading the Grid
Every chart has the same basic shape, even when the layout differs between brands.
| Chart element | What it means | What to watch for |
|---|---|---|
| Lift point height (rows) | Height of the load above or below ground level | Negative rows are lifts into a trench or below track level |
| Radius / reach (columns) | Horizontal distance from the swing centre of the machine | Measured from the machine's centre of rotation, not the track edge |
| Over-front values | Boom pointing straight ahead over the tracks | Usually the lowest figures — this is the weakest direction |
| Over-side values | Boom swung 90° to the side | Higher, because the track width resists tipping |
| End / long dipper columns | Figures for an extended stick | Extra reach always costs capacity |
| Asterisk or bold cells | Hydraulic-limited rather than stability-limited | Do not assume you can "add a bit" here |
Worked example: you need to place a 320 kg concrete panel 3 m from the machine centre, at ground level, over the front. You look up the row for 0 m height, the column for 3 m radius, over-front — and the cell says 300 kg. The machine is 20 kg short. The fix is to reposition the machine 500 mm closer, or slew so the lift happens over the side.
The Four Mistakes
1. Forgetting the attachment weight
The chart assumes a bare machine with a standard bucket. A quick coupler, hydraulic thumb, tilt bucket or grab all reduce the payload you have left. Weigh or look up the attachment before doing the maths — a 45 kg thumb and a 70 kg tilt bucket is 115 kg off every figure on the chart.
2. Measuring radius from the wrong point
Radius is measured from the machine's centre of rotation, which sits roughly under the boom pivot, not from the front of the tracks. Measuring from the track edge can understate the radius by nearly a metre on a 2 tonne machine — enough to put you 20–30% over the safe figure.
3. Ignoring ground conditions
Charts assume firm, level ground. On soft fill, on a cross-slope, or with one track in a rut, the tipping load falls well below the published value. There is no chart correction for this; you reduce capacity by judgement, or you level and pack the ground first.
4. Treating the swing as free
Slewing a suspended load creates a sideways force the chart does not model. A load that is safely within limits when stationary can destabilise the machine when swung quickly. Move the controls gently and let the load settle between movements.
Below-Ground Lifts Deserve Extra Care
Laying pipe into a trench is the most common below-ground lift on a compact site, and it is where charts are most often misread. Two things change: the radius grows as you reach down and out, and the trench edge itself may be the thing that fails rather than the machine.
Keep the spoil pile well back, shore or batter the trench where required, and remember that the operator's view into a deep trench is poor — use a signal person rather than leaning out of the cab.
When the Load Is Too Close to the Limit
If your regular work sits within 15% of the rated figure, you are operating with no margin for a wet day, a soft patch or a slightly heavier delivery. Options, in order of preference:
- Move the machine closer to the load — a few hundred millimetres of radius buys a surprising amount of capacity.
- Specify the next size class up, or a model with an optional counterweight and wider track stance.
- Split the load. Two lifts are always cheaper than one accident.
- Use equipment designed for lifting rather than an excavator being asked to do a crane's job.
Keep the Chart With the Machine
Print the chart, laminate it, and keep it in the cab pocket. It is a legal expectation on many sites, and it is the fastest answer when someone on site asks the question that causes most incidents: "can we lift this?"
Every machine in our mini excavator range ships with full lift and dimension documentation. If you are sizing a machine around lifting rather than digging, start with the heaviest object you move in a typical week — models such as the SDLE35 and SDLE42 are specified with attachment and lift work in mind.
