Carboplatin Calculator

How to use this carboplatin dose calculator

What this calculator does

This tool reproduces a common two-stage carboplatin calculation. First, it estimates creatinine clearance using the Cockcroft-Gault equation from Sex, Age, Weight, and Serum creatinine. It then treats that estimate as the renal-function input to the Calvert formula, where Target AUC sets the intended drug exposure. The calculator reports GFR, Carboplatin dose, and Maximum dose. It is an educational calculation aid, not a chemotherapy order, treatment recommendation, or substitute for an oncology protocol, measured kidney function, pharmacist verification, or clinician judgment.

When to use it

It is useful for checking the arithmetic in an AUC-based carboplatin workflow, comparing how a changed creatinine value alters the estimated dose, reproducing a worked example for teaching, or creating an auditable spreadsheet of the current inputs and outputs. For clinical use, the relevant regimen and institution-specific dosing rules control. The U.S. National Cancer Institute's AUC-based carboplatin dosing information letter describes the Calvert relationship and the commonly cited 125 mL/min GFR cap for calculating a maximum dose.

How to calculate

1. The calculator opens with a ready-to-use demonstration: Male, age 50 years, weight 78 kg, serum creatinine 1.2 mg/dL, and target AUC 7 mg/mL·min. The results and a validated Excel workbook are available immediately.
2. Replace the demonstration values with the values you want to examine. Results update live; no Calculate button is needed.
3. Read GFR first, then Carboplatin dose, and compare that dose with Maximum dose. The detail table shows the intermediate creatinine-clearance value, sex factor, and both dose calculations.
4. Select Download Excel to create a current-state .xlsx workbook containing the inputs, outputs, and calculation details. Reset clears the demonstration and current results. After Reset, Download Excel is disabled until all required inputs are complete and valid again.

Input guide

Sex is required and accepts Male or Female. In this Cockcroft-Gault implementation, Female applies a factor of 0.85 to the otherwise identical estimate. Changing this control therefore changes GFR and Carboplatin dose, but it does not change Maximum dose because that maximum depends on Target AUC. A common mistake is treating this factor as a general biological rule outside the historical equation; it is specifically part of the formula used here.

Age is a required whole number from 18 to 120 years; the demonstration uses 50. Higher age lowers the Cockcroft-Gault estimate when all other inputs stay fixed because the numerator contains 140 minus age. Enter years only, not a birth date or an age with units typed into the field.

Weight is required in kilograms and accepts 1 to 500 kg; the demonstration uses 78 kg. A higher entered weight increases the estimated creatinine clearance in this direct equation. The appropriate weight convention can be clinically important, especially in obesity or unusual body composition, so do not assume the raw scale weight is always the protocol-required value.

Serum creatinine is required in mg/dL and accepts 0.1 to 30; the demonstration uses 1.2 mg/dL. Because creatinine is in the denominator, a larger value lowers estimated clearance and therefore lowers the Calvert dose. Do not enter µmol/L without converting it first, and do not use commas as decimal marks; this calculator uses a dot for decimals.

Target AUC is required in mg/mL·min and accepts 0.1 to 20; the demonstration uses 7. A higher AUC raises both the calculated dose and the maximum dose proportionally. The target is a regimen-level clinical choice, not something this calculator selects. Use the target specified by the applicable oncology protocol.

Output guide

GFR is displayed in mL/min and, in this calculator, is the Cockcroft-Gault creatinine-clearance estimate used in the dose formula. It is driven by Sex, Age, Weight, and Serum creatinine. Carboplatin dose is the uncapped Calvert-formula result in milligrams using that estimated renal function and Target AUC. Maximum dose is Target AUC × 150 mg, corresponding to a GFR input capped at 125 mL/min before adding the Calvert constant of 25. If the calculated dose is above that maximum, the page flags the comparison; it does not silently change the formula result.

The Calculation detail table shows five rows: creatinine clearance before the sex factor, the sex multiplier, the final estimated GFR / creatinine clearance, the Calvert dose, and the AUC-based maximum dose. These are calculation checkpoints rather than separate clinical recommendations.

Worked example

With Male, Age 50, Weight 78 kg, and Serum creatinine 1.2 mg/dL, Cockcroft-Gault gives (140 – 50) × 78 ÷ (72 × 1.2) = 81.25 mL/min. The male sex factor is 1.00, so the displayed GFR remains 81.25 mL/min. With Target AUC 7, the Calvert dose is 7 × (81.25 + 25) = 743.75 mg, displayed as 743.8 mg. The AUC-based maximum is 7 × 150 = 1,050 mg. These values are the exact demonstration shown when the calculator first opens.