Water Potential Calculator
Calculate plant water potential from solute, pressure, matric and gravity components. Use −iCRT for solute potential and compare two samples to predict water movement.
Project inputs
Change any value to update the result. Units, boundaries and conditional fields are validated by this calculator’s own engine.
Water Potential Calculator results
How to use the water potential calculator
This water potential calculator uses a dedicated engine, live visual and explanations specific to this problem. Review the assumptions before using the output for purchasing, design, grading, pricing or operational decisions.
Add every water-potential component
This water potential calculator reports total Ψ as solute potential plus pressure potential, matric potential and gravitational potential. Each sample can use a directly entered solute potential or calculate Ψs from molarity, ionization factor and absolute temperature with the van’t Hoff relation.
Compare two plant or solution samples
Enter roots, cells, soil, xylem or laboratory solutions as Sample A and Sample B. The difference is calculated as A minus B. In a passive comparison, water tends to move from the higher, less negative water potential toward the lower, more negative water potential.
Units and signs matter
Pressure potential may be positive in turgid cells, while solute and matric components are commonly negative. Elevation contributes a small gravitational term per meter. The calculator converts kPa, bar and psi entries to MPa before combining them.
Biological interpretation
Real tissues have membranes, resistance, active transport, changing solute concentration and nonequilibrium conditions. Use the result as a thermodynamic direction estimate and report assumptions, temperature and all included components.
Water Potential Calculator questions
What is the solute-potential formula?
For an ideal dilute solution, Ψs = −iCRT, where i is the ionization factor, C is molarity, R is the gas constant and T is temperature in kelvins.
Which way does water move?
Water tends to move from higher water potential to lower water potential when a pathway exists.
Why is water potential often negative?
Dissolved solutes lower free energy relative to pure water, and matric attraction can lower it further. Pressure can offset those negative components.