Chemistry
Gibbs' Phase Rule Calculator
Count the degrees of freedom of a system from its components, phases and independent reactions.
Your inputs
Change any value to update the result instantly.
Degrees of freedom F
2
Components
2
Phases
2
Independent reactions
0
Reading
Choose 2 variables freely without changing the phases present
The factor of 2 assumes temperature and pressure are the only free intensive variables. Subtract one independent reaction for each chemical equilibrium that links the components.
What this calculator does
Counts how many intensive variables can be changed independently without altering the phases present.
What your result means
Zero means an invariant point such as a triple point; larger values mean more freedom to change temperature or composition.
Formula and working
F = C − P + 2 − R
- 1
Collect the inputs
Components (C) = 2; Phases (P) = 2; Independent reactions (R) = 0; Variable factor = 2
- 2
Apply the formula
F = C − P + 2 − R
- 3
Result
Degrees of freedom F = 2
Frequently asked questions
Symbols and assumptions
- C
- Components
- P
- Phases
- R
- Independent reactions
- F
- Degrees of freedom
- • Equilibrium between the phases.
- • Temperature and pressure are the only free intensive variables unless you reduce the factor.
Sources and review
Reviewed 2026-09-22 · Next review 2027-09-22
- • Surface, field and gravitational effects are ignored.
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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