Millimeter of water to Psi Converter (and vice versa)

Created by: tinycalcs.com/en
Number of supported units: 2
Last update: 2026

This converter allows you to convert millimeters of water [mmH₂O, mmWS] to psi or psi to millimeters of water [mmH₂O, mmWS]. Calculations are performed in both directions. The calculation result and the entered value are displayed with up to 20 decimal places for maximum accuracy.

1 millimeter of water [mmH₂O, mmWS] ≈ 0.0014 psi1 psi ≈ 703.0696 millimeters of water [mmH₂O, mmWS]

Convert millimeters of water to psi

There are two simple ways to convert millimeters of water [mmH₂O, mmWS] to psi. In the first calculation method, the value in millimeters of water [mmH₂O, mmWS] is divided by the rounded conversion factor of 703.0696. The second method multiplies the value in millimeters of water [mmH₂O, mmWS] by the rounded conversion factor of 0.0014.

  • Psi ≈ millimeters of water [mmH₂O, mmWS] ÷ 703.0696
  • Psi ≈ millimeters of water [mmH₂O, mmWS] * 0.0014

However, rounded conversion values are only suitable for rough conversions, as rounding errors can occur in the calculation result. The most accurate conversion of millimeters of water [mmH₂O, mmWS] to psi can be achieved using the following calculation method.

  • Psi = millimeters of water [mmH₂O, mmWS] ÷ 4,535.9237 * 6.4516

Convert psi to millimeters of water

Converting psi to millimeters of water [mmH₂O, mmWS] is easy and can be done in two ways. The first method involves multiplication, in which the value in psi is multiplied by the rounded conversion factor of 703.0696. The second variant is a division. Here, the value in psi is divided by the rounded conversion factor of 0.0014.

  • Millimeters of water [mmH₂O, mmWS] ≈ psi * 703.0696
  • Millimeters of water [mmH₂O, mmWS] ≈ psi ÷ 0.0014

However, rounded conversion values do not allow for exact calculations because rounding errors can occur in the calculation result. The most accurate conversion of psi to millimeters of water [mmH₂O, mmWS] can be achieved using the following calculation method.

  • Millimeters of water [mmH₂O, mmWS] = psi * 4,535.9237 ÷ 6.4516

Converter

Decimal places

How it's calculated

Factor: 
≈ 703.07
Psi = Millimeters of water ÷ 4,535.9237 * 6.4516
Millimeters of water = Psi * 4,535.9237 ÷ 6.4516

To all available units

Millimeters of water

Standard atmospheres

Millipascals

Decapascals

Millipascals

Gigapascals

Millipascals

Megapascals

Millipascals

Micropascals

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