In general, the selection process is as follows:

• Determine the best method for weighing: Decide on the load conditions for the load cell (tension, compression, bending, etc.).
• Select the Rated Capacity: Use the following calculation:
  L ≥ (( f1 × W1 + W2 ) × f2 × f3) / N
  L:  Rated capacity of the load cell to be determined
  N:  Number of load cells used
  W1: Maximum load of the weighed material (capacity of the scale)
  W2: Dead weight of equipment (tare)
  f1:  Dynamic coefficient (A coefficient that takes into account that a load greater than the input mass is applied due to a drop or other impact when weighing a material.), 1.1 to 1.5, usually 1.3
  f2:  Eccentricity coefficient (a coefficient that accounts for the concentration of load on a particular load cell due to unbalanced loading of the weighed material), 1.1 to 1.3, usually 1.2
  f3:  Unbalance coefficient (a coefficient that takes into account the fact that when supporting a device, it is stable when supported at 3 points but becomes unbalanced when supported at 4 or more points) 1.0 for N≤3, 1.2 for N≥4.
  
  For example, if the load weight is 3 kg and the number of load cells used is 1, the rated capacity of the load cell should be 3.9 kg. To measure 3 kg, you need a load cell with a capacity of at least 3.9 kg.
• Check if the required resolution can be displayed.
• Make a selection based on the strength of the load cell.
  

Example of “3. Check if the Required Resolution Can Be Displayed”:
Suppose we want to measure 3 kg with 0.1 g increments.
We have prepared a load cell with a rated capacity of 6 kg. The input sensitivity of the indicator we want to use is 0.15 μV.
Let's see if this combination can achieve the desired minimum display of 0.1 g.

The specifications of the load cell and indicator are as follows:

In the example above, applying a load of 3 kg will result in an output of 5 mV.

If you want to display in 0.1 g increments from 0 to 3 kg, this 0.1 g is the “minimum display value”.
Measuring 3 kg in 30,000 increments [0.1 g] means a resolution of 1/30,000.
The output value per 0.1 g is:

The input sensitivity of the indicator is 0.15 μV.
Since this value is smaller than 0.167 μV, it is possible to display in 0.1 g increments with this indicator.
If the input sensitivity of the indicator were larger than 0.167 μV, it would not be possible to display in 0.1 g increments.