Renal & Electrolytes

Urine Output (mL/kg/hr) Calculator

Urine output per kg per hour, the usual way to judge kidney perfusion and stage AKI.

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

Turn on JavaScript to use this calculator, or open it in the web app.

Formula

Volume / Weight / Time

Reference: AKI if under 0.5 mL/kg/h for 6 h (KDIGO)

How it is used

• KDIGO 2012 urine criteria: under 0.5 mL/kg/h for 6–12 h is stage 1, for 12 h or more stage 2; under 0.3 for 24 h or anuria for 12 h is stage 3. Stage by the worse of urine and creatinine.
• Urine output often falls before creatinine rises, which lags 24–48 h behind the injury.
• Measure hourly against weight in critical illness; check the catheter for a kink or clot before calling it oliguria.

Same formula as the app. Open it in the web app.

Related one-pagers

• Electrolyte ImbalancesCheck urine output and kidney function first.
• Shock Types at a GlanceCardiogenic · Cool, mottled; crackles, JVD; low urine output · Reperfuse an MI; norepinephrine; add an inotrope; MCS if failing
• Peripheral Vascular EmergenciesReperfusion chemistry · Dark urine, rising potassium and CK, acidosis · Labs and urine output
• Blood Products and TransfusionAcute hemolytic · Fever, back pain, low BP, dark urine, oozing; usually an ID error · Send labs and bag; support BP and urine output

For education and exam preparation only. Follow your institution’s protocols. For education and exam preparation only. Verify results independently and follow your institution’s protocols. Not a substitute for clinical judgment.