This allows for comparisons like the following:
The first traces of modern humans date back to more than two hundred thousand years ago. But it was only in the last five thousand years (i.e. during less than three percent of human history) that the first class societies arose. Modern industrial capitalism surfaced just a few hundred years ago (i.e. in the last 0.25 percent of human history). In other words, if human history took place over the course of a single day, capitalism only unfolded three minutes before midnight.1
The calculator below can be useful for making comparisons like the one in the example quote, where historical events or periods are expressed as fractions or percentages of the total length of human history or some other time period. It allows us to visualize the relative length of these periods and to compare them in a more intuitive way.
To use the calculator you should enter the length of time period, f.e. 400 years, and the length of whole timeline, f.e. 200 000 years. There is a second calculator below the first, which goes as a supplement, allowing you to enter only percentage, f.e. 0.25%, as the whole period is considered to be 100%.