With this tool you can customize and refine your mesh knowing the length of the first element.
You can download the Excel file here: Bias Factor
You can download the last Excel file here: Bias Factor
If you input are edge length, number of divisions and length of first element you can use this Excel file: Bias Factor Custom
The equations for calculating the length of the first element of the mesh using Bias Factor are:
For calculating the second length you must multiply the growth rate and the first length, for the third length you must multiply the second length and the growth rate again and so on.