# IV Infusion Rate Calculator (R₀ = Css · CL) Calculate the continuous IV infusion rate that maintains a target steady-state plasma concentration: R₀ = Css · CL, where Css is the target concentration and CL is clearance. At steady state, the infusion rate equals the elimination rate. If the IV solution concentration (mg/mL) is provided, the tool additionally derives the infusion-pump delivery rate in mL/h, which is what the pump is actually set to in clinical practice. This is an IV-only tool — bioavailability F is not applicable. Reaching steady state requires approximately 4–5 half-lives. Not medical advice. > Canonical page: https://elysiatools.com/en/tools/iv-infusion-rate-calculator - **Category:** Health - **Keywords:** iv infusion, infusion rate, R0, k0, Css, clearance, steady state, pump rate, continuous infusion, pharmacokinetics, pk, drug, medicine ## Overview The IV Infusion Rate Calculator uses R₀ = Css · CL to calculate the continuous IV infusion rate needed to maintain a target steady-state plasma concentration. Enter the target concentration and clearance, and optionally provide the IV solution concentration to derive the pump rate in mL/h. This tool is for IV infusion calculations and is not medical advice. ## Inputs - **Target Css (mg/L)** (number): Target steady-state plasma concentration. Must be positive. - **Clearance CL (L/h)** (number): Drug clearance in L/h. Must be positive. - **IV solution concentration (mg/mL, optional)** (number): Optional concentration of the IV solution. When provided, the pump rate in mL/h is derived. - **Decimal Places** (number) ## When to use - Calculate the required continuous infusion rate in mg/h from a target Css and drug clearance. - Convert the calculated drug infusion rate into a pump setting in mL/h when the IV solution concentration is known. - Check pharmacokinetic calculations for steady-state IV infusion planning or education. ## How it works - Enter a positive target steady-state concentration, Css, in mg/L. - Enter a positive clearance value, CL, in L/h. - The calculator multiplies Css by CL to return the infusion rate R₀ in mg/h. - Optionally enter the IV solution concentration in mg/mL to calculate the pump rate in mL/h; results can be rounded to the selected number of decimal places. ## Use cases - Estimate a continuous IV drug infusion rate from target plasma concentration and clearance. - Translate a dose rate in mg/h into an IV pump rate using the prepared solution concentration. - Support pharmacokinetics coursework, calculation review, and clinical education. ## Frequently asked questions ### What formula does the calculator use? It uses R₀ = Css · CL, where Css is the target concentration and CL is clearance. ### What units should I enter? Enter Css in mg/L and clearance in L/h. The infusion rate is returned in mg/h. ### How is the pump rate calculated? When solution concentration is provided in mg/mL, pump rate equals infusion rate divided by solution concentration and is returned in mL/h. ### Is the IV solution concentration required? No. Css and clearance are required for the mg/h result. The solution concentration is optional and is needed only for the mL/h pump rate. ### Does the calculator account for bioavailability or time to steady state? No. It is an IV-only calculation, so bioavailability F does not apply. Reaching steady state generally takes about 4–5 half-lives. ## Related tools - [A-a Gradient (Alveolar-Arterial O₂)](https://elysiatools.com/en/tools/a-a-gradient-calculator): Calculate the alveolar-arterial O₂ gradient to distinguish hypoxemia causes. 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