torr to pascals

The torr is the vacuum scientist's unit — named for Evangelista Torricelli, who invented the mercury barometer in 1644 — and it is defined as exactly 1/760 of a standard atmosphere. Since one standard atmosphere is exactly 101,325 Pa, one torr is exactly 133.322368421053 Pa. A vacuum chamber at 1×10⁻³ torr is 0.133 Pa; a roughing pump pulling 0.1 torr is at 13.3 Pa.

1 torr = 133.3224 pascals, and 1 pascal = 0.007500617 torr. One fixed factor covers the whole range: multiply torr by 133.3224. Worked: 10 torr = 1,333.224 pascals; 100 torr = 13,332.24 pascals.

By EnginStack Editorial Team | Reviewed against NIST, BIPM and primary-source documentation About →
torr
101,325 pascals
760 torr = 101,325 pascals 760 pascals = 5.70046879 torr

Verified against NIST Special Publication 811 and BIPM SI definitions. The conversion factor is exact and traceable to the 1959 treaty constants.

torr to pascals

The torr and the pascal are both pressure units anchored to the same definition: 1 atm = 760 torr = 101,325 Pa exactly, with both relationships fixed by convention. The torr's practical home is vacuum work — sputter coating, freeze drying, semiconductor processing, all specified in torr or millitorr — while the pascal and its multiples dominate every other branch of SI pressure. Every torr value on a chamber readout has an exact pascal equivalent, and converting between them never involves a rounded constant.

pascals = torr × 133.322368421053
1 torr = 133.322368421053 pascals — 101,325 Pa ÷ 760
The factor is exact: 1 atm = 760 torr = 101,325 Pa.

Worked Examples

Example 1: Convert one torr

1 × 133.3223684211 = 133.32 Pa

Example 2: Convert a roughing-pump vacuum of 0.1 torr

0.1 × 133.3223684211 = 13.33 Pa

Example 3: Convert one standard atmosphere

760 × 133.3223684211 = 101,325 Pa

Common torr to pascals Conversions

torrpascalsContext
1 torr133.3 PaThe definitional anchor.
100 torr13,332 PaA rough vacuum.
760 torr101,325 PaOne standard atmosphere.
0.1 torr13.3 PaA typical roughing-pump vacuum.
0.001 torr0.133 PaHigh vacuum — 1 millitorr.

Engineering Context

The pascals to torr page runs this factor backward. In the pressure hub, atm to Pa carries the same 101,325 Pa definition, and psi to kPa handles the US-industrial branch. Vacuum coating and freeze drying also touch the temperature family, since sublimation rates depend on both.

Vacuum practice is divided into bands, and the unit changes as the pressure falls: rough vacuum from 760 down to about 1 torr, medium vacuum to 10⁻³ torr, high vacuum to 10⁻⁷, and ultra-high vacuum below that. The torr survives across the whole range mostly because the gauges do. A thermocouple or Pirani gauge is still calibrated and dialled in torr, so even laboratories that report in pascal convert at the display. Below roughly one pascal the practical units become the pascal and the millibar, and the torr is reserved for the older instruments still in service.

More: Pa to torr · atm to Pa · psi to kPa · Pressure Guide · Pressure Hub

Related Unit Converters

pascals to torr Atmospheres to Pascals psi to kPa Pressure Conversion Guide Pressure Converters

Frequently Asked Questions

What is a torr exactly?

A torr is exactly 1/760 of a standard atmosphere — defined so that one standard atmosphere is 760 torr. Since a standard atmosphere is exactly 101,325 Pa, one torr is exactly 101,325/760 = 133.322368421053 Pa.

Is a torr the same as a millimeter of mercury?

For practical purposes, yes — the torr was defined to equal one mmHg at standard conditions, and the two are numerically identical to the precision of any real measurement. The torr is the unit of definition; mmHg is the same value read from a mercury column.

Why does vacuum science use torr instead of pascals?

History and convenience: vacuum instruments grew out of the mercury barometer (Torricelli's invention), so the field standardized on torr and millitorr. Modern labs often quote both — a 1×10⁻³ torr process chamber is 0.133 Pa — which is why the conversion is a daily tool.