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⚗️ Pharmaceutical QC Calculation Tool

Assay DF Ratio Calculator
for Pharmaceutical QC

Calculate a corrected Assay % between Sample and Standard using the Dilution Factor Ratio, with optional weight and purity correction. Get the DF Ratio, Area Ratio, final Assay result, and a full step-by-step mathematical log — compliant with ICH Q2(R2) and USP <621>.

⚗️ Sample vs Standard 📊 DF Ratio Correction ⚖️ Weight Correction 💊 ICH Q2(R2) 📋 USP <621> 🧮 Full Math Log
1
Enter Standard & Sample
peak areas
›
2
Enter Standard & Sample
Total DF values
›
3
Optionally add weights
and purity
›
4
Click Calculate for the
corrected Assay %
›
5
Copy or print the
complete QC report
⚗️ Calculator 📘 Concept & Beginner Guide
⚗️ Assay Calculation with DF

Assay DF Ratio — Sample vs Standard

Formula Used in Assay Calculation
When weights are entered (full formula):
Assay (%) = (Sample Area ÷ Standard Area) × (Standard Wt ÷ Sample Wt) × (Sample DF ÷ Standard DF) × (Purity ÷ 100) × 100

When weights are not entered (simplified):
Assay (%) = (Sample Area ÷ Standard Area) × (Sample DF ÷ Standard DF) × 100

Where: DF Ratio = Sample DF ÷ Standard DF
Peak area from Standard injection. Add multiple readings to auto-average.
Peak area from Sample injection. Add multiple readings to auto-average.
From the Dilution Factor Calculator
From the Dilution Factor Calculator
Accurately weighed Standard
Accurately weighed Sample
Nominal label claim
Purity value
✅
Assay Calculation Complete
Assay Result (%)
—
Final assay percentage
DF Ratio (Smp÷Std)
—
Dilution correction factor
Area Ratio (Smp÷Std)
—
Raw peak area ratio
Std DF
—
Spl DF
—
Wt Ratio (Spl/Std)
—
Label Claim
—
Standard Purity (%)
—
🔢 Assay Math Log

Traceable Step-by-Step Assay Calculation Log

⚠️ Disclaimer
BestPharmaTools.com provides this Assay DF Ratio Calculator strictly for educational and informational purposes. It is an independent, unaffiliated online tool and is not a validated laboratory instrument, controlled GMP document, or a substitute for your organization's approved Quality Management System, Standard Operating Procedures, or review by qualified QA/QC personnel. All data entered is provided solely by the user; BestPharmaTools.com does not verify, endorse, or take responsibility for its accuracy, completeness, or suitability for any regulatory, clinical, or commercial use. Any output — including results viewed, copied, or printed — is used entirely at the user's own discretion and risk. BestPharmaTools.com and its owners/affiliates accept no liability for any decisions, actions, losses, or damages arising from use of this tool. Always verify calculations independently and follow your organization's validated systems and approved SOPs for any official, regulatory, or GMP-related documentation.