Elastomer chemical compatibility
Compare common media with NBR, FKM, EPDM, HNBR, CR and silicone.
MATEMATICAO-ring calculator
Calculate O-ring squeeze, stretch and gland fill.
Enter geometry and tolerances. Selecting a row highlights its matching dimension in the drawing.
| Input (mm) | Symbol | Nominal size | Standard/Fit | Lower tolerance limit | Upper tolerance limit | Min. | Max. |
|---|---|---|---|---|---|---|---|
| Bore diameter | d4 | — | — | ||||
| Piston diameter | d9 | — | — | ||||
| Groove diameter | d3 | — | — | ||||
| Groove width | b1 | — | — | ||||
| Groove radius | r | — | — | ||||
| O-ring inside diameter (23 °C) | d1 | — | — | ||||
| O-ring cross-section (23 °C) | d2 | — | — |
| Calculation results | Concentric position | Eccentric position | ||
|---|---|---|---|---|
| Min. | Max. | Min. | Max. | |
| Compression incl. R (%) | 40.84 % | 42.06 % | 39.61 % | 43.29 % |
| Compression incl. R (mm) | 1.41 mm | 1.46 mm | 1.37 mm | 1.50 mm |
| Gap g | 0.10 mm | 0.10 mm | 0.10 mm | 0.11 mm |
| Housing fill (%) | 106.90 % | 110.11 % | 103.69 % | 113.32 % |
| Stretch OR inside diameter (%) | 4.00 % | 4.12 % | 3.88 % | 4.24 % |
| R (%) | 1.00 % | 1.03 % | 0.97 % | 1.06 % |
| OR cross-section incl. R (mm) | 3.46 mm | 3.57 mm | 3.36 mm | 3.67 mm |
| t (mm) | 2.00 mm | 2.06 mm | 1.94 mm | 2.12 mm |
| Total compression force (N) | — | — | — | — |
Indicative geometric result. Force requires compound, hardness, pressure, temperature and manufacturing tolerances.
Tutti i dettagli
3 righe| Check | Valore |
|---|---|
| Squeeze | 18,571429 |
| Stretch | 4 |
| Fill | 76,358155 |
COME FUNZIONA
Non solo un risultato. Anche la spiegazione.
Checks basic circular O-ring geometry using squeeze, stretch and gland-fill percentage.
squeeze = (section - depth - gap / 2) / section; fill = ring area / groove areaIpotesi e limiti
Indicative geometry only. It does not replace compound selection, tolerances, pressure, temperature or design validation.
Un esempio semplice
A 3.5 mm O-ring in a 2.8 mm groove gives about 20% squeeze before clearance.
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Formula visibile · Aggiornato l’8 settembre 2026