A classic teaching equation
Tetens published this two-constant exponential in 1930, and Murray (1967) popularized it in the meteorological literature. It has the same shape as the Magnus form, with round historical constants, and reproduces the saturation curve to roughly 1% between 0 and 50 °C.
Its simplicity made it a workhorse in early numerical weather models and it remains a common textbook example for relating temperature and humidity.
When to use it
Tetens is a fine choice for quick estimates, teaching, or matching the output of a legacy model that used it. For accuracy-sensitive work the Alduchov–Eskridge Magnus set or Buck 1996 are better choices at essentially the same computational cost.
It is included here for completeness and historical interest, and it appears in the main calculator's side-by-side comparison.
Compare with other formulas
See this and every other formula side by side, with the live deviation from IAPWS-95 at your temperature, on the main calculator. The Antoine equation has its own page.
References
Every formula on this page is implemented from, and validated against, the following primary standards and papers.
- On the computation of saturation vapor pressure (Murray 1967) — Tetens 1930; Murray 1967, J. Appl. Meteorol. 6:203 — the Tetens form
- IAPWS R6-95(2018) / Wagner & Pruss 2002 — International Association for the Properties of Water and Steam — the reference standard
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