IV Therapy

Infusion Time Calculator

How long a bag will last at a set rate.

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

Time (hr) = volume (mL) ÷ rate (mL/hr)

How it is used

• Use this to plan when to hang the next bag and to check that a medication finishes within its stability time.

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

Related one-pagers

• Pulmonary EmbolismAround alteplase, the label restarts anticoagulation once the aPTT or thrombin time is twice normal or less, and the PERT Consortium holds UFH during the infusion and restarts it without a bolus; ESC 2019 lets UFH run, and CMAJ 2026 continues LMWH on schedule. The order should say who restarts heparin and when.
• Sepsis and Septic Shock BundleAntibiotic time is when the infusion starts, not when it is ordered or verified. Hang the first dose in the ED rather than waiting for ICU transfer.
• Sedation, Pain and Delirium ScalesOpioids: fentanyl suits instability and renal failure but accumulates in fat after days of infusion, and large rapid boluses can cause chest wall rigidity. Morphine releases histamine and its active metabolite accumulates in AKI. Hydromorphone is about 7 times as potent as IV morphine, a classic mix-up. After 5–7 days of infusion, taper rather than stop: iatrogenic withdrawal (tachycardia, hypertension, sweating, diarrhea, yawning, agitation) mimics delirium. Many protocols reduce 10–20% a day or convert to enteral methadone; practice varies.
• Heart FailureDOSE (NEJM 2011; 308 patients) found boluses every 12 h and a continuous infusion equivalent; 2.5 times the oral dose given IV produced more diuresis and only a transient creatinine rise. A spot urine sodium below 50–70 mEq/L at 2 h, or urine output below 100–150 mL/h over the first 6 h, signals an inadequate response: double the dose (HFA position statement, Mullens 2019), then add a second diuretic (2022 guideline 2a).

Drip cards with a dose ↔ mL/h converter

Related calculators

• IV Pump Rate (mL/hr)
• mcg/min to mL/hr
• Units/hr to mL/hr (Heparin, Insulin)

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.