Formulation Tools · Solid Oral Dosage · CMC
Tablet Compression Force Calculator
Calculate tensile strength, compression pressure, and friability for pharmaceutical tablet development, tech transfer, and in-process control planning.
Quick Answer
Tablet tensile strength σ (MPa) = 2F / (π × D × T) from diametral breaking force F (N), diameter D, and thickness T. Compression pressure = force ÷ punch face area. Friability % = [(weight before − after) / before] × 100; USP limit ≤1% for uncoated tablets. Use tensile strength and pressure — not hardness alone — for formulation tabletability and CMC comparability.
Friability % = [(Wbefore − Wafter) / Wbefore] × 100
Tablet Compression Calculations
Calculate tensile strength from hardness and dimensions, estimate compression pressure from target hardness, or evaluate friability from weight loss.
Enter total weight of the tablet sample before and after the friabilator test (4 minutes at 25 RPM per USP <1261>). You may enter multiple individual tablet weights or a pre-weighed total.
Typical Hardness Targets by Tablet Type
| Tablet Type | Hardness (N) | Hardness (kP) | Notes |
|---|---|---|---|
| Immediate release (IR) | 80–150 N | 8–15 kP | Balance of hardness and dissolution |
| Extended / sustained release (ER/SR) | 120–200 N | 12–20 kP | Higher hardness to control polymer matrix integrity |
| Orally disintegrating (ODT) | 20–50 N | 2–5 kP | Must disintegrate ≤30 s (USP); typically unit-dose packaged |
| Chewable | 50–80 N | 5–8 kP | Soft enough to chew comfortably |
| Sublingual | 30–60 N | 3–6 kP | Rapid disintegration under tongue required |
| Effervescent | 40–80 N | 4–8 kP | Anhydrous processing; friability less critical |
How to Use
Worked Example — Tensile Strength
F = 100 N, D = 9 mm = 0.009 m, T = 4.5 mm = 0.0045 m
σ = (2 × 100) / (π × 0.009 × 0.0045) = 200 / 0.0001272 = 1.572 MPa
Classification: Acceptable (1–2 MPa range)
Compression pressure at 100 N over 63.6 mm²: P = 100 / 63.6 mm² = 100 / (63.6 × 10&sup6; m²) = 1.57 MPa — note this is very low; real-world tablet presses apply force in kN range.
Pharma formulation & CMC context
Compression characterization supports preformulation tabletability studies, exhibit batch release, and ANDA/NDA comparability after scale-up or post-approval changes. Document tensile strength and compression pressure alongside dissolution and friability in development reports per USP <1062> tablet compression characterization principles.
Link results to the Moisture Calculator when granulation LOD affects compactibility, and to the Coating Solution Calculator when film coat weight gain must balance core hardness for pan attrition.
Evidence & sources
- Gamlen: USP tablet compression characterization overview
- FDA Guidance: BE for immediate-release solid oral dosage forms
- Competitive landscape: Pharmaguddu pharmaceutical calculators cover yield, Cpk, and equipment capacity but not integrated tensile strength, compression pressure profile, and friability in one tabbed tool. Tableting education sites such as Gamlen tableting guides explain σ = 2F/πDT conceptually without free bedside arithmetic. NovaPharmaNews combines three calculation modes, USP friability pass/fail, and formulation hub cross-links — no login required.