Online Tools and Calculators > Health and Fitness > FENa Calculator

FENa Calculator

Urine Sodium (UNa):
Urine Creatinine (UCr):
Plasma Sodium (PNa):
Plasma Creatinine (PCr):

About FENa Calculator

The FENa Calculator is used to calculate the fractional excretion of sodium.

FENa Definition

The fractional excretion of sodium (abbreviated as FENa) is the percentage of the sodium filtered by the kidney which is excreted in the urine. It is measured in terms of plasma and urine sodium, rather than by the interpretation of urinary sodium concentration alone, as urinary sodium concentrations can vary with water reabsorption.


The FENa calculation formula is as follows:

FENa = (UNa × PCr) / (UCr × PNa) × 100%


FENa ValueCategoryDescription
< 1%prerenal diseasethe physiologic response to a decrease in renal perfusion is an increase in sodium reabsorption to control hypovolemia.
> 2% or 3%acute tubular necrosis or other kidney damageeither excess sodium is lost due to tubular damage, or the damaged glomeruli result in hypervolemia resulting in the normal response of sodium wasting.
intermediateeither disorderIn renal tract obstruction, values may be either higher or lower than 1%. The value is lower in early disease, but with renal damage from the obstruction, the value becomes higher.


Frequently Used Miniwebtools:

All Miniwebtools (Sorted by Name):


If you like FENa Calculator, please consider adding a link to this tool by copy/paste the following code:

Automatic Mode

Copyright © Miniwebtool.com | | Terms and Disclaimer | Privacy Policy | Contact Us