The glomerular filtration rate or GFR is the amount of fluid filtered from the capillaries into the Bowmans capsule of the kidneys per unit time. The GFR can be expressed as the following formula: | The glomerular filtration rate or GFR is the amount of fluid filtered from the capillaries into the Bowmans capsule of the kidneys per unit time. The GFR can be expressed as the following formula: |