pH and pOH Calculator

Free pH and pOH Calculator determines the pH and pOH of the solution in a short span of time. Provide chemical formula, and pH of density in the given input section and hit the calculate button to get the respected pH and pOH values quickly.

pH and pOH Calculator: Finding the pH and pOH of a chemical solution can be difficult for you. But it is easy by using our handy pOH and pH Calculator tool. It takes the required data and provides the pOH and pH values. Here we are giving the simple steps to calculate the pH and pOH of a chemical solution easily. Along with the explanation, you can also check pH, pOH formulas, and their relationship.

What is pH and pOH?

pH is defined as the negative logarithm of H+ ion concentration. So, it is abbreviated as the power of hydrogen. pH is a measuring tool for acids and bases. The formula of pH is along the lines:

pH = -log[H+]

pOH is the measure of alkalinity and acidity of a solution by finding the concentration of OH- ions. It is the negative logarith of OH- ion concentration.

pOH = -log[OH-]

Relation Between pH and pOH

pH is the negative logarithm of hydronium ion and pOH is the negative logarithm of hydroxy ion concentration.

i.e pH = -log[H+] or -log[H3O+]

pOH = -log[OH-]

We know that [H3O+][OH-] = 10-14 at 250C

By taking log on both sides

log[H3O+][OH-] = log(10-14)

log[H3O+] + log[OH-] = -14

-log[H3O+] - log[OH-] = 14

pH + pOH = 14

How to Calculate pH and pOH?

  • Get the H+ ion concentration.
  • Find the negative logarithm of the value to know pH value.
  • Subtract 14 from pH value to find the pOH value.


Find the pH and pOH of the solution in which the concentration of hydronium ion is 8 x 10-8 M.


The hydronium ion concentration is 8 x 10-8 M

pH = -log[H3O+]

= -log[8 x 10-8]

= 7.09

pOH = 14 - pH

= 14 - 7.09

= 6.91

Therefore, pH = 7.09, pOH = 6.91

Have a glance at the online calculator tools from & enhance your chemistry skills and understand the concepts easily.

FAQs on pH and pOH Calculator

1. How to calculate pH and pOH?

To calculate pH, take the negative log of the hydrogen ion concentration. pOH is obtained by subtracting 14 from the pH value.

2. What is the formula to calculate pOH?

The formula to calculate pOH is pOH = -log[OH-].

3. What is pOH in relation to pH?

The relation between pH and pOH is pOH = 14 - pH.

4. What is pH measurement?

In chemistry, the term pH denotes the potential of hydrogen. pH is the measurement for alkalinity and acidity. The usual pH range is from 0 to 14.