Calculator inputs
Use the fields below to estimate a weight-based and renal-aware regimen summary.
Example data table
| Patient | Antibiotic | Dose weight | Renal estimate | Suggested regimen | Course total |
|---|---|---|---|---|---|
| Adult, 35 years, 72 kg | Amoxicillin | 72.00 kg | 100.00 mL/min | 500 mg every 8 hours for 7 days | 10,500 mg |
| Adult, 68 years, 94 kg | Levofloxacin | 82.00 kg | 38.00 mL/min | 750 mg every 48 hours for 5 days | 2,250 mg |
| Child, 6 years, 22 kg | Cephalexin | 22.00 kg | 110.00 mL/min | 375 mg every 8 hours for 10 days | 11,250 mg |
Formula used
Adult renal estimate: Creatinine clearance = ((140 − age) × dosing weight) ÷ (72 × serum creatinine). Multiply by 0.85 for females.
Pediatric renal estimate: Estimated eGFR = 0.413 × height in centimeters ÷ serum creatinine.
Body surface area: BSA = √((height in cm × weight in kg) ÷ 3600).
Ideal body weight: Male = 50 + 2.3 × inches over 60. Female = 45.5 + 2.3 × inches over 60.
Adjusted body weight: AdjBW = IBW + 0.4 × (actual weight − IBW) when actual weight exceeds 120% of IBW.
Adult dose model: Base per-dose reference × intensity factor. Daily total = per dose × doses per day, then capped by the library maximum.
Pediatric dose model: Daily total = mg/kg/day × dosing weight × intensity factor, then split by interval and capped by the library maximum.
Renal adjustment model: The selected antibiotic may reduce daily exposure and extend intervals when the renal estimate falls below preset cutoffs.
How to use this calculator
1. Select the patient type and antibiotic. The library uses simplified outpatient-style reference entries.
2. Enter age, sex, actual weight, height, and serum creatinine. These values power the renal and weight calculations.
3. Choose a weight method. Auto uses adjusted body weight for adults above 120% of ideal body weight.
4. Set treatment intensity, duration, and any interval override. Leave the interval on Auto to allow renal spacing.
5. Add liquid concentration or tablet strength if you want mL-per-dose or units-per-dose outputs.
6. Review the regimen summary, warnings, and graph. Export the result to CSV or PDF for documentation.
7. Confirm the output against your local formulary, allergy history, infection source, pregnancy status, culture data, and specialist guidance.
FAQs
What does this calculator estimate?
It estimates a reference antibiotic regimen from age, weight, kidney function, interval settings, and maximum daily caps. It is designed for educational planning and workflow support.
Does it replace a prescriber or pharmacist review?
No. Final dosing still depends on infection source, organism susceptibility, allergy history, pregnancy status, organ function trends, and local antimicrobial guidance.
Why does the calculator ask for height?
Height supports body mass index, body surface area, ideal body weight, and adjusted body weight calculations. Those values help the tool choose a dosing weight.
When should I use Auto weight selection?
Auto is useful for adults when actual body weight is much higher than ideal body weight. It switches to adjusted body weight above 120% of ideal.
Does it handle dialysis patients?
No. Dialysis timing, membrane type, and post-dialysis redosing are too specific for this simplified model. Use a site-specific dialysis protocol instead.
Can I use it for children?
Yes, it has a pediatric branch using mg/kg/day logic. Neonatal dosing and many subspecialty scenarios still require dedicated protocols.
What do the export buttons include?
The CSV includes the result summary plus a dose-by-dose course table. The PDF captures the visible result card and chart for sharing.
Why might the final dose look lower than expected?
The tool may reduce exposure because of renal cutoffs, interval spacing, or the antibiotic’s maximum daily library cap. Review the warning panel for the reason.