Medications & Dosing calculators

50 live medications & dosing calculators inside Health & Medical on The Online Calculator 24. Every engine shows its formula, the worked steps behind the default figures, and the standard or dataset the method comes from.

Live Medications & Dosing tools

• Weight-Based Dose & Liquid Concentration Calculator — Calculate accurate pediatric and adult weight-based medication doses (mg/kg/day), dosing frequency splits (q6h, q8h, q12h), and liquid suspension volume in mL.
• Body Surface Area (BSA) & Chemotherapy Dosing Calculator — Calculate accurate human Body Surface Area (BSA in m²) using the Mosteller, Du Bois, and Haycock formulas to establish oncology chemotherapy and narrow-therapeutic-index medication dosages.
• Renal Dose Adjustment Calculator — A Cockcroft-Gault creatinine clearance feeding a linear renal-elimination model: the fraction of drug that depends on the kidney scales with the fraction of function left.
• Hepatic Dose Adjustment Calculator — Child-Pugh class mapped to empirical dose reductions, weighted by how much of the drug’s clearance is hepatic and how much shunting the first-pass effect hides.
• Pediatric Dose Calculator — The three 19th-century bedside rules — Clark, Young, Fried — computing a child’s dose from the adult dose, kept here for the comparison they enable.
• Geriatric Dose Calculator — A structured form of the prescribing maxim “start low, go slow”: estimate residual clearance, shrink the factor, and stack a Beers-list penalty on top.
• Loading Dose Calculator — The one-time dose that fills the volume of distribution immediately instead of waiting five half-lives for steady state.
• Maintenance Dose Calculator — The steady-state drip: at plateau the body eliminates exactly what goes in, so the rate equals clearance × target concentration.
• Oral Bioavailability Calculator — The fraction of an oral dose that reaches circulation intact — AUC ratio corrected for the two doses, absorbing gut and first-pass liver into one number.
• IV to PO Conversion Calculator — The IV-to-oral switch number: match the daily IV exposure by dividing by the drug’s bioavailability — arithmetic that presumes a working gut.
• Drug Half-Life Calculator — The time for the plasma concentration to halve — printed two ways from the two roads to it: the compartment model and the measured pair.
• Time to Steady State Calculator — The clock that steady state keeps: time depends only on half-life, and every extra 50% of the gap costs one more half-life.
• Drug Accumulation Calculator — How many times above the first dose the plateau lands when the interval is shorter than the half-life — the geometric series of residual drug.
• Volume of Distribution Calculator — The notional volume the dose would have to dissolve in to match the measured plasma level — a partition coefficient wearing an anatomical disguise.
• Clearance Rate Calculator — The volume of fluid fully cleared of drug per unit time — the dose-adjusting number, computed from the most robust measurement available: dose ÷ AUC.
• AUC Calculation Calculator — Total drug exposure: the area under the concentration-time curve built with linear-up/log-down trapezoids and closed by a terminal extrapolation.
• Peak and Trough Calculator — The plateau band a multiple-dose regimen lives in: steady-state peak and trough from the IV-bolus superposition model.
• Cmax Estimate Calculator — The top of the single and plateau curves for a one-compartment oral model — where peak-related toxicity lives.
• Cmin Estimate Calculator — The concentration just before the next dose — Cmax decayed across the dosing interval, adjusted for an absorption lag.
• Therapeutic Window Calculator — Where a measured level sits inside the therapeutic band, plus the population therapeutic index that says how much margin the drug has at all.
• Narrow Therapeutic Index Calculator — The population margin between half-effective and half-toxic doses — and the FDA’s narrow-index definition that tightens bioequivalence.
• Warfarin Dose Calculator — The CHEST antithrombotic-therapy nomogram in arithmetic: shift the weekly total by a percentage band keyed to how far the INR sits from target.
• INR Target Calculator — The indication-specific INR band a VKA is titrated into — and the ISI arithmetic that makes INR comparable across thromboplastins.
• Heparin Dose Calculator — The weight-based unfractionated heparin protocol — bolus, infusion, and the aPTT nomogram steps that replaced empirical dosing.
• LMWH Dose Calculator — Enoxaparin dosing by indication and kidney: the treatment/prophylaxis split, the renal collapse to once-daily, and the obesity question.
• Vancomycin Dose Calculator — The 2020 ASHP/IDSA vancomycin guidance as arithmetic: mg/kg of actual weight, interval by renal function, and an AUC/MIC target replacing trough-only monitoring.
• Aminoglycoside Dose Calculator — Once-daily gentamicin/tobramycin dosing on adjusted body weight with CrCl-scaled interval — the standard extended-interval protocol.
• Phenytoin Dose Calculator — A Michaelis-Menten dose proposal for phenytoin: because hepatic metabolism saturates inside the therapeutic window, level changes demand non-linear dose changes.
• Digoxin Dose Calculator — Renal-clearance-based digoxin maintenance dosing: the drug is ~renal elimination, so the CrCl drives the dose as much as the target does.
• Lithium Dose Calculator — Renal-function-driven lithium dosing: the ion is handled almost entirely by the kidney, so dose equals target concentration times its clearance.
• Theophylline Dose Calculator — Clearance-based theophylline dosing with the smoking/heart-failure modifiers — the archetype of a drug whose window is measured in single mg/L.
• Cyclosporine Dose Calculator — Weight-based cyclosporine dosing with the standard linear trough-to-dose adjustment — the arithmetic every transplant clinic runs weekly.
• Tacrolimus Dose Calculator — Weight-based tacrolimus dosing with linear trough adjustment — the calcineurin inhibitor backbone of modern transplant immunosuppression.
• Metformin Dose Calculator — The renal-function dosing ladder for metformin: eGFR bands set the maximum, and the bands are the current FDA/EMA relabeling, not the old creatinine folklore.
• Insulin Total Daily Dose Calculator — The weight-and-stage estimate of total daily insulin dose — the denominator under basal, bolus, carb ratio and correction-factor calculations.
• Basal Insulin Dose Calculator — The fasting-glucose titration rule for basal insulin (glargine/degludec): a conservative ladder of +1–2 U per review, never more.
• Bolus Insulin Dose Calculator — The two-term mealtime bolus: carbohydrate coverage plus a glucose correction — the arithmetic every pump and MDI regimen is built on.
• Carb Ratio Calculator — The 450/500/550 rule: divide the total daily insulin into a grams-per-unit carbohydrate estimate — the food half of bolus maths.
• Correction Factor Calculator — The 1800 rule translated to correction factor: how much one unit of insulin drops glucose — the repair term of every bolus.
• Insulin Sensitivity Factor Calculator — The empirical correction factor: a documented high glucose, a known no-food insulin dose, and the resulting fall — the test version of the 1800 rule.
• Opioid Equianalgesic Calculator — The equianalgesic table applied: any opioid dose scaled to oral morphine equivalents using the 30 mg reference points.
• Morphine Equivalent Calculator — The sum of every opioid a patient takes scaled to morphine equivalents — the single number behind prescribing-monitoring-programme risk rules.
• Opioid Rotation Calculator — A two-step opioid rotation: equianalgesic conversion first, then the cross-tolerance haircut second — in the wrong order it becomes an over-dose.
• Steroid Equivalency Calculator — The anti-inflammatory equivalency table (hydrocortisone 20 : prednisone 5 : methylpred 4 : dex 0.75) used for every steroid switch and taper audit.
• Antibiotic Duration Calculator — Duration guidance from the syndrome-shortest-trials era: uncomplicated infections stopped in 3–7 days, with the “why not shorter” question increasingly answered by RCTs.
• Antimicrobial Prophylaxis Calculator — WHO/ASHP surgical prophylaxis arithmetic: weight-band dosing, interval re-dosing by half-life, and the hard 24-hour stop.
• Contrast Dose Calculator — Weight-scaled iodinated contrast volume with the current renal-risk banding — the dose side of a contrast ordering form.
• Radiation Dose Calculator — The linear-quadratic BED/EQD2 conversion radiotherapy uses to compare schedules with different fraction sizes on one scale.
• Chemotherapy Dose Calculator — The two dosing rails of chemotherapy: BSA-scaled mg/m² agents and the carboplatin Calvert equation driven by GFR and target AUC.
• Biologic Dose Calculator — The per-agent dosing map of biologics: some scale with weight, some are fixed, and the weight bands are hard thresholds, not curves.

Reading a Medications & Dosing result

A number on its own is the weakest thing a calculator can give you, so these tools pair each output with the comparison that gives it meaning: the gap to a target, the band the value falls in, or what a realistic swing in one input does to the answer. When a figure looks wrong, that is usually the fastest place to check — re-run it with one input moved and see whether the change lines up with the formula printed above the result.

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