Matplotlib figure size unit is inches and default dpi is 100

• figure unit, ie figsize=(8, 6): inch
  • figsize=(width, height)
• default dpi rcParams['figure.dpi']: 100

The native figure size unit in Matplotlib is inches, deriving from print industry standards. However, users may need to specify their figures in other units like centimeters or pixels

Because of the default rcParams['figure.dpi'] = 100, one can mentally divide the needed pixel value by 100

https://matplotlib.org/stable/gallery/subplots_axes_and_figures/figure_size_units.html