Carboplatin dosing is based on kidney function and the target AUC (area under the curve). This Carboplatin Calculator estimates your carboplatin dose using the Calvert formula and converts results into mg for practical prescribing.
Enter your target AUC, serum creatinine, and weight, then choose the creatinine clearance method. The calculator outputs the estimated total carboplatin dose (mg) and the dose per mL if you provide vial concentration.
What the Carboplatin Calculator computes
Carboplatin dosing commonly uses the Calvert equation, which links the dose to kidney clearance. The key inputs are your target AUC and a clearance estimate derived from serum creatinine and body size.
- Target AUC (mg·min/L): the treatment intensity prescribed by your oncology team.
- Renal function: estimated as CrCl (creatinine clearance) in mL/min.
- Carboplatin dose: calculated in mg from AUC and CrCl.
Core formula: Calvert equation
The calculator uses the standard form of the Calvert equation for carboplatin:
Dose (mg) = AUC × (CrCl + 25)
Where:
- Dose (mg) is the estimated total carboplatin dose for the treatment cycle.
- AUC is the prescribed target value in mg·min/L.
- CrCl is the estimated creatinine clearance in mL/min.
- 25 is a constant representing non-renal clearance.
How the calculator estimates creatinine clearance (CrCl)
Most dosing workflows estimate CrCl using the Cockcroft–Gault equation. Your calculator lets you choose the method and weight basis to match common oncology practice.
Cockcroft–Gault (typical default)
When using Cockcroft–Gault, the calculator estimates CrCl as:
CrCl (mL/min) = ((140 − age) × weight) / (72 × SCr) and multiplies by 0.85 for females.
Variables:
- Age in years.
- Weight in kg (choose actual, ideal, or adjusted based on your setting).
- SCr is serum creatinine in mg/dL.
Unit conversion for serum creatinine
Serum creatinine may be reported as mg/dL or µmol/L. If you enter µmol/L, the calculator converts to mg/dL using:
mg/dL = µmol/L ÷ 88.4
Weight input: which weight should you use?
CrCl estimates depend on which weight is used in Cockcroft–Gault. Many institutions use actual body weight, while others use adjusted body weight for patients with obesity or use ideal body weight in specific protocols.
Choose the option that matches your clinical protocol. If your protocol specifies a particular weight rule, follow that rule even if the calculator offers alternatives.
Ideal body weight (IBW) reference
If you choose ideal weight, the calculator uses standard IBW formulas:
- IBW (kg) for men = 50 + 2.3 × (height in inches − 60)
- IBW (kg) for women = 45.5 + 2.3 × (height in inches − 60)
Height is required for IBW-based calculations.
Dose rounding and clinical safety
Carboplatin doses are often rounded to practical vial preparation steps. This calculator provides a mathematically estimated dose; your oncology team may apply rounding rules or protocol limits.
- Consider protocol-specific dose capping and rounding.
- Some protocols use a minimum serum creatinine or a creatinine “floor” in specific scenarios.
- Always verify with institutional pharmacy or prescribing guidelines.
Practical Example 1: Typical outpatient dosing
A 62-year-old patient (female) has a target AUC of 5 mg·min/L. Serum creatinine is 1.1 mg/dL, and the patient’s weight is 70 kg. Using Cockcroft–Gault with the chosen weight basis yields an estimated CrCl, and the calculator computes:
- Dose (mg) = 5 × (CrCl + 25)
- The output gives the estimated total carboplatin dose for that cycle.
This approach helps standardize dosing across patients by tying dose to renal function and the prescribed AUC.
Practical Example 2: Serum creatinine in µmol/L
For a patient whose lab reports serum creatinine as 120 µmol/L, the calculator converts it to mg/dL before estimating CrCl. If the target AUC is 6 mg·min/L and CrCl is estimated from the converted value, the calculator outputs the total carboplatin dose in mg.
- Conversion uses mg/dL = µmol/L ÷ 88.4.
- The final dose uses the Calvert equation with CrCl + 25.
This reduces dosing errors caused by unit mismatches.
How to use the calculator (step-by-step)
- Enter patient details: age, sex, height (if needed), and weight.
- Enter serum creatinine and select the unit (mg/dL or µmol/L).
- Pick the weight basis used by your protocol (actual, ideal, or adjusted).
- Set the target AUC in mg·min/L.
- (Optional) Add vial concentration so the calculator can convert mg dose to an estimated mL volume.
The calculator then calculates CrCl, applies the Calvert equation, and displays the dose in mg (and mL if provided).
Important limitations
This calculator is for dose estimation and supports preparation and education. It cannot replace clinical judgment, protocol decisions, or pharmacy verification.
- Renal function estimation has limitations, especially in extremes of body size or rapidly changing kidney function.
- Different protocols may use different AUC targets, CrCl calculation approaches, or rounding rules.
- Always follow your local oncology and pharmacy guidelines.
Frequently Asked Questions
How is the carboplatin dose calculated from AUC?
Carboplatin dose is commonly calculated with the Calvert equation: dose (mg) equals AUC times (CrCl plus 25). CrCl is an estimate of creatinine clearance in mL/min derived from age, serum creatinine, and body weight. The AUC comes from the treatment plan.
What does “CrCl + 25” mean in the Calvert formula?
In the Calvert equation, CrCl represents kidney clearance, and the constant 25 accounts for non-renal clearance. Adding 25 converts the clearance estimate into the total clearance term used for dosing. This is why carboplatin dose depends on both renal function and the target AUC.
Which weight should I use for the creatinine clearance calculation?
Many protocols use actual body weight, but some use adjusted or ideal body weight for patients with obesity or other special considerations. The calculator lets you select the weight basis. Use the option your institution’s protocol specifies, because different weight choices change the estimated CrCl and final dose.
How do I handle serum creatinine reported in µmol/L?
If serum creatinine is reported in µmol/L, convert it to mg/dL before using Cockcroft–Gault. The standard conversion is mg/dL equals µmol/L divided by 88.4. This calculator performs the conversion automatically when you select the correct input unit.
Can this calculator replace clinical dosing decisions?
No. This tool estimates dose based on the Calvert equation and a chosen CrCl method. Real-world dosing may require protocol limits, dose rounding, creatinine “floor” rules, and clinical context. Always confirm with your oncology team and pharmacy before administering carboplatin.