Medical Calculators

Clinical reference tools for healthcare professionals, students, and informed patients.

⚠️ For educational and reference use only. Do not use for clinical decision-making without consulting a licensed medical professional. Always verify drug doses with current prescribing references.

Patient Weight (kg)

Dose per kg (mg/kg)

Frequency

Drug Concentration (mg/mL)

Single Dose (mg)0

Single Dose (mL)0

Daily Total (mg)0

Daily Total (mL)0

⚠️ Verify against current drug references. Renal/hepatic impairment may require dose adjustment.

Volume to Infuse (mL)

Infusion Time (hours)

Drop Factor (gtt/mL)

Drip Rate (gtt/min)0

Flow Rate (mL/hr)0

Drops per Second0

Sex

Height (cm)

Actual Body Weight (kg)

Ideal Body Weight (Devine)0 kg

Adjusted Body Weight0 kg

BMI0

Weight vs IBW0%

Age (years)

Sex

Weight (kg)

Serum Creatinine (mg/dL)

CrCl (Cockcroft-Gault)0

Kidney Function Stage—

Current Weight (kg)

Target Weight (kg)

Daily Caloric Deficit

Fat to Lose0 kg

Total Calorie Deficit Needed0 kcal

Estimated Weeks0

Projected Completion—

Weight-Based Drug Dosing

Many medications — particularly antibiotics, anticoagulants, and chemotherapy agents — are dosed by weight (mg/kg) to achieve therapeutic plasma concentrations. Actual body weight is used for most drugs; however, ideal body weight (IBW) or adjusted body weight (AdjBW) may be more appropriate for obese patients. Always consult the manufacturer's prescribing information or clinical pharmacist when in doubt.

IV Drip Rate Calculation

Formula: gtt/min = (Volume × Drop Factor) ÷ (Time in minutes). Macrodrip chambers deliver 10, 15, or 20 gtt/mL and are used for routine fluid administration. Microdrip chambers deliver 60 gtt/mL and are used for precise, low-volume infusions (pediatrics, ICU). Always use an infusion pump for critical medications — never rely on gravity drip alone for medications where accuracy is critical.

Ideal Body Weight & Adjusted Body Weight

The Devine Formula: Men IBW = 50 + 2.3 × (inches over 5 ft); Women IBW = 45.5 + 2.3 × (inches over 5 ft). Adjusted Body Weight (AdjBW) is used for obese patients: AdjBW = IBW + 0.4 × (ABW − IBW). This adjustment is used for dosing aminoglycosides, heparins, and some other drugs in patients whose actual weight significantly exceeds IBW.

Creatinine Clearance (Cockcroft-Gault)

CrCl (mL/min) = [(140 − Age) × Weight] / (72 × SCr), multiplied by 0.85 for females. CrCl estimates glomerular filtration rate (GFR) and is critical for renal dosing adjustments. Stages: ≥90 = Normal; 60–89 = Mildly decreased; 30–59 = Moderately decreased; 15–29 = Severely decreased; <15 = Kidney failure. Many renally-cleared drugs (vancomycin, aminoglycosides, metformin) require CrCl-based dose adjustments.

Caloric Deficit & Weight Loss Timeline

The widely-used estimate is that 7,700 kcal of deficit = ~1 kg of body fat. A sustainable deficit of 500 kcal/day produces approximately 0.5 kg of fat loss per week. Deficits above 1,000 kcal/day risk muscle catabolism, nutrient deficiencies, and metabolic adaptation (starvation response). For clinical settings, Very Low Calorie Diets (VLCD, <800 kcal/day) should only be undertaken under medical supervision.

Community Discussion

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RN Patricia • 2 days ago

"The IV drip rate and drug dosage tools are handy for quick double-checks. Clear labeling prevents misreads — well done."

PharmD Jose • 1 week ago

"Would love to see a Cockcroft-Gault calculator for renal dosing. Otherwise this is a solid clinical reference tool."