What the calculators cover
Every calculator page also explains its formula in plain steps, shows a worked example and points out the slips that cause most problems. Use the tool for the answer, and the guide to understand it.
Planning and formulation
The Batch Size Calculator converts a master formula into the quantities for a chosen batch. The API Requirement Calculator works out how much active ingredient to dispense once overage and the assay of the lot are taken into account. The Tablet Weight Calculator back-calculates tablet weight from the API dose and its percentage in the formula, and the Mixer Capacity Calculator checks whether a batch fits the working volume of a blender.
Coating, powders and testing
The Coating Material Calculator gives the dry coating, suspension and vehicle quantities for a target weight gain. The Bulk and Tapped Density Calculator returns Carr’s index and the Hausner ratio to describe powder flow. The Weight Variation Calculator, the Deliverable Volume Calculator and the Tablet Friability Calculator support three routine pharmacopoeial tests.
Yield and reconciliation
Reconciliation compares what a stage should have produced with what it did produce. The calculators follow the stages of a solid dosage line: granulation, compression, coating, encapsulation, blister and packing. The Percentage Yield Calculator handles the general case, and the Unit Converter moves values between nanograms, micrograms, milligrams, grams, kilograms, pounds and ounces.
Latest articles
- Compression Force to Pressure: kN to MPa: Convert punch force to pressure for round and capsule tooling.
- MACO Calculation for Cleaning Validation: Dose-based, 10 ppm and health-based limits, with swab and rinse limits.
- Expiry Date Calculation in Pharma: Turn a shelf life into an expiry date using three common rules.
- Cost per Tablet Calculation in Pharma: The true cost of each good tablet from materials, labour and packaging.
- What a 1% Yield Drop Costs in Pharma: Tablets lost, batches lost and the yearly cost of a one-point drop.
- Batches per Month: Press Speed and OEE: Plan monthly output from press speed, OEE and changeovers.
How to use the results
A calculator gives a theoretical figure. Whether a result is acceptable depends on the limits in your approved batch record, your validated process and the current pharmacopoeia, none of which a general tool can know. Treat the output as a cross-check on your own calculation, and keep the unit, the balance and the sampling method the same from one figure to the next. When a yield or a weight falls outside its limit, the guide on each calculator page lists the usual causes in the order worth checking.
For background on the reasoning behind the tools, read the articles on batch reconciliation, where yield is lost between stages, setting yield limits from batch data and tablet coating defects. Each article links back to the calculator it relates to, so a worked example can be repeated with your own figures.
The tools are built and maintained by Sajjad Ahmad, who has spent 14 years in pharmaceutical manufacturing. See how the calculators work and are tested, browse the articles, or send questions and corrections through the contact page.
For reference and education only. Always follow your own approved procedures.