Vancomycin Dosing Calculator
Estimate an empiric starting dose of intravenous vancomycin from body weight, following the 2020 ASHP/IDSA guideline. Enter actual body weight for the loading and maintenance dose ranges, and add creatinine clearance for a suggested dosing interval. This gives an initial estimate only — definitive dosing uses AUC-guided therapeutic monitoring and pharmacy input, not a fixed formula.
About empiric vancomycin dosing
Weight-based dosing gives a reasonable first vancomycin dose; from there, AUC-guided therapeutic drug monitoring drives every adjustment for serious MRSA infection. Source: Rybak MJ et al., “Therapeutic monitoring of vancomycin … a revised consensus guideline of the ASHP, IDSA, PIDS and SIDP,” Am J Health-Syst Pharm 2020;77(11):835–864.
Frequently asked questions
How is empiric vancomycin dosed?
The 2020 ASHP/IDSA guideline recommends a loading dose of 20–35 mg/kg of actual body weight (not to exceed 3,000 mg) for seriously ill adults, followed by a maintenance dose of 15–20 mg/kg every 8–12 hours in patients with normal renal function. This calculator applies those ranges to the weight you enter, and suggests an interval from the creatinine clearance. The exact dose within each range depends on the infection, the target and the institution.
Why is AUC monitoring important?
The 2020 guideline moved away from trough-only dosing to AUC-guided dosing for serious MRSA infections, targeting an AUC/MIC of 400–600 mg·h/L. That target cannot be read off body weight alone — it needs measured vancomycin levels and either Bayesian software or first-order equations. So this tool is for choosing a reasonable first dose, after which levels guide every subsequent adjustment.
What weight should I use?
Both the loading and maintenance doses use actual (total) body weight in the guideline, with the loading dose capped at 3,000 mg. In extremes of body weight the standard mg/kg dosing may need to deviate to reach a therapeutic AUC, which is one reason levels and pharmacy review matter. Doses are usually rounded to a practical amount, commonly the nearest 250 mg.
How does kidney function change the interval?
Vancomycin is cleared renally, so a lower creatinine clearance means a longer interval. A common empiric starting point is roughly every 8–12 hours above about 90 mL/min, every 12 hours around 50–90, every 24 hours around 15–49, and dosing by levels below that or on dialysis. These bands vary between institutions and are only a starting suggestion — this calculator shows a band, not a prescription.
What are the limits of this calculator?
It gives an empiric adult IV estimate only. It does not perform AUC or pharmacokinetic calculations, does not cover paediatric, dialysis, oral (for C. difficile) or intraperitoneal dosing, and does not replace measured levels or clinical pharmacy. Always confirm the dose and monitoring plan locally. This is an educational reference, not medical advice.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
More medical calculators
eGFRCreatinine ClearanceBody Surface AreaCorrected CalciumAnion GapA1C to eAGHOMA-IRQUICKIGMICholesterol RatioMean Arterial PressureQTcWaist-to-Hip RatioWaist-to-Height RatioLean Body MassPack-YearVO₂ MaxMELD ScoreFramingham RiskASCVD RiskCHA₂DS₂-VAScHAS-BLEDWells DVTWells PEMELD 3.0PREVENT RiskCHA₂DS₂-VAGeneva ScorePERC RuleChild-PughCURB-65Glasgow Coma (GCS)FIB-4 IndexCorrected SodiumSerum OsmolalityAPRIFatty Liver IndexNAFLD Fibrosis ScoreCentor ScoreFeNaqSOFALVH (ECG)ESR (VSH)Thymol TurbidityMaddrey's DFA-a GradientNEWS2ANCWinters' FormulaShock IndexAlvarado ScoreReticulocyte IndexFree Water DeficitPadua ScoreGlasgow-BlatchfordCIWA-ArMMEMaintenance FluidsBishop ScoreSteroid ConversionHEART ScorePediatric DoseSOFA ScoreTransferrin SaturationSF Syncope RuleParkland FormulaInsulin CorrectionCaprini ScoreNIHSSPSI / PORT Lab unit converters →