ONE FORMULA, ONE ANSWER
Ideal Dilute Solution pH Calculator
Calculate concentration-based pH with an activity coefficient of one. Choose input units and calculate one value within the stated conditions.
Inputs
Calculations run in this browser. Scientific notation such as 1.2e-3 is supported. Do not group thousands.
Result
Concentration approximation pH
Enter values and select Calculate.
pH ≈ −log₁₀(c_H/(1 mol/L))
Assumptions
Required: positive hydrogen ion concentration normalized by 1 mol/L. Ideal dilute approximation with activity coefficient one; exact pH uses hydrogen ion activity. No forced 0–14 clipping or dissociation equilibrium solving.
Displayed values are floating-point approximations. Design safety factors and unprovided error contributions are not calculated.
Formula references and credits
NaNa Lab created the code, descriptions, icons and preview images. Text, figures and code from the linked references have not been reproduced.
Physical constants: NIST / CODATA 2022. The values of μ₀ and ε₀ are measured recommendations, not exact defining constants. Values and precision notes are in the source record.
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