pH Calculator
Calculate pH, pOH, and [OH⁻] from hydrogen-ion concentration. This free online science & engineering calculator runs entirely in your browser — no signup, no data sent anywhere.
Inputs
Results
How It Works (Formula & Method)
pH is the negative base-10 logarithm of the hydrogen-ion concentration: pH = −log₁₀[H⁺]. At 25°C, pH + pOH = 14, and [H⁺][OH⁻] = 1×10⁻¹⁴, which gives the hydroxide concentration. Values below 7 are acidic, above 7 basic.
Worked Example
Below is a worked example using the calculator's default values. The same numbers are pre-filled in the form above so you can press Calculate and see the result without typing anything.
Inputs used:
- Hydrogen-Ion Concentration [H⁺] (mol/L): 0.0001
With these inputs, the calculator computes the metrics shown in the Results panel. Change any value and press Calculate again to see how the result responds — the live widget and the chart both update instantly.
Frequently Asked Questions
What does the pH Calculator compute?
The pH Calculator takes 1 input value and returns 3 results. Calculate pH, pOH, and hydroxide concentration from the hydrogen-ion concentration of a solution.
Is my data sent to a server?
No. The pH Calculator runs entirely in your browser using static JavaScript. Your inputs are never transmitted to CalculatorHive or any third party, and nothing is stored after you close the page.
Is this calculator free to use?
Yes. Every calculator on CalculatorHive is completely free. There is no signup, no paywall, and no usage limit. The site is supported by display advertising and affiliate partnerships, which are clearly labeled.
How accurate is the result?
The math is mathematically exact for the inputs you provide. Real-world accuracy depends on how accurately your inputs reflect the real situation — defaults are typical values, not guarantees.