Prepared and reviewed by Sajjad Ahmad, pharmaceutical manufacturing professional with 14 years of experience.
Last reviewed: October 30, 2026
Why this page exists
Every calculation on PharmainformCalc should be traceable. This page shows the formula behind each tool, the standard it follows where one exists, how the tools were checked, and what has been corrected so far. If something here does not match your own references, please tell us.
How each calculator works
| Calculator | How it calculates | Source or standard |
|---|---|---|
| Batch Size | Units = target × (1 + overage %); batch weight = units × unit weight; API = units × dose; excipients = batch weight − API | Standard batch-record arithmetic |
| Tablet Weight | Tablet weight = API dose ÷ (API % w/w ÷ 100); each excipient = weight × its % | Standard formulation arithmetic |
| Coating Material | Gain per tablet = core weight × gain %; dry coating = gain × tablets; suspension = dry coating ÷ solids %; spray time = suspension ÷ spray rate | Standard process arithmetic |
| API Requirement | Net API = label claim × batch × (1 + overage %); gross API = net API ÷ assay | Certificate-of-analysis assay correction |
| Bulk and Tapped Density | Bulk density, tapped density, Carr’s Index = (tapped − bulk) ÷ tapped × 100, Hausner ratio = tapped ÷ bulk | USP <616> and <1174>; Ph. Eur. 2.9.34 and 2.9.36 |
| Mixer Capacity | Working volume = total volume × fill %; capacity = working volume × bulk density | The qualified range of your own equipment governs |
| Percentage Yield | Actual ÷ theoretical × 100 | 21 CFR 211.103; the status bands are general guides only |
| Unit Converter | Milligram base, with 1 lb = 453,592.37 mg and 1 oz = 28,349.52 mg | Exact unit definitions |
| Weight Variation | Uniformity of mass limits of ±10%, 7.5% and 5% by average weight; the 20-unit USP table; acceptance value for 10 or 30 units | BP and Ph. Eur. uniformity of mass; USP <2091>; USP <905> |
| Deliverable Volume | Each container as a % of label; Stage 1 and Stage 2 decisions for multiple-unit and single-unit containers | USP <698> |
| Six reconciliation tools | Theoretical quantity compared with actual; coated, filled and blistered stages converted to unit counts with average unit weights | Standard batch-record practice; 21 CFR 211.103 |
How the tools were tested
These tools are practically tested by author and other pharma professionals by using various practical examples.
Each calculator was also run in a browser with test inputs, and every output was compared with a separate calculation. The most recent review ran more than 350 checks across all 16 tools. These included every pair of units in the Unit Converter, every flow class of the Carr’s Index scale, the weight limits on both sides of each band boundary, and every decision path of the deliverable volume test. Each article’s worked examples were recomputed independently before publishing.
Standards and sources
Where a pharmacopoeial chapter or regulation is named, the figures follow the published text as understood at the time of review. Pharmacopoeias are revised, so always check the current official edition before relying on a limit. Typical ranges quoted in articles, such as yields or compaction pressures, are general guidance and not specifications.
Assumptions and limits
- The tools are for reference and education. They do not replace your validated procedures, batch manufacturing records or professional judgment.
- Status labels such as “Excellent yield” use general bands. Your approved limits come from your own process validation.
- Worked examples in articles use illustrative numbers and prices, and say so.
- Nothing on the site is medical, legal or regulatory advice.
Corrections log
Errors are corrected on the page and recorded here.
| Date | Change |
|---|---|
| 30 Oct 2026 | Weight Variation: the BP capsule limit at exactly 300 mg corrected to ±7.5% (below 300 mg stays ±10%). |
| 30 Oct 2026 | Deliverable Volume: the Stage 1 retest rule now follows USP <698>. An average below 100% together with a borderline container fails. |
| 30 Oct 2026 | Unit Converter: very small results now keep enough significant digits. |
| 30 Oct 2026 | Bulk and Tapped Density and Percentage Yield: a result sitting exactly on a class boundary (for example Carr’s Index of 10.0%) is now classified correctly. |
| 30 Oct 2026 | Articles: a deliverable volume worked example corrected, a wrong statement in the yield limits article corrected, the batch reconciliation article updated to six stages, and an ICH Q8(R2) note added to the API overage article. |
Report an error
If a result or a statement does not match a source you trust, send the page address, the values you entered and the reference to the contact page. Each report is reviewed, and the page is corrected where the report is right.