pH Calculator
pH calculator
Solve pH chemistry from any one value: [H+], [OH-], pH, or pOH. Includes full profile output with pKw control and a visual acidity scale.
Result
pH = 3
strongly acidic • pOH 11
Live profile
pH scale
[H+]
1.0000e-3 mol/L
[OH-]
1.0000e-11 mol/L
pH
3
pOH
11
Reference points
Battery acid
pH 1
Lemon juice
pH 2
Coffee
pH 5
Pure water
pH 7
Blood
pH 7.4
Seawater
pH 8.1
Household ammonia
pH 11.6
Current condition is strongly acidic. Formula set: pH = -log10([H+]), pOH = pKw - pH, [OH-] = 10^-pOH.
Formula
pH = -log10([H+]) Symbol legend
| Symbol | Meaning | Unit | Copy |
|---|---|---|---|
\mathrm{pH} | Potential of hydrogen | pH units | |
[\mathrm{H}^+] | Hydrogen ion concentration | mol/L |
- Enter hydrogen ion concentration in mol/L.
- Take base-10 logarithm of concentration.
- Apply negative sign to get pH.
Example
Worked example: [H+] = 1.0 x 10^-3 M
- 1 [H+] = 0.001
- 2 pH = -log10(0.001)
- 3 pH = 3
The solution pH is 3.
How
- Enter [H+] concentration in mol/L.
- Ensure concentration is positive.
- Read pH result instantly.
Avoid
- Entering zero or negative concentration values.
- Using natural log instead of base-10 log.
- Confusing [H+] with [OH-] input.
Checks
Best fit
pH Calculator is built for calculate ph from hydrogen ion concentration using ph = -log10([h+]) with fast chemistry-ready validation. If pH Calculator does not match the input scope, compare the answer with a second method.
Input check
Check \mathrm{pH} before calculating: it means potential of hydrogen and is measured in pH units.
Sanity check
For pH Calculator, use the worked example as a quick benchmark: The solution pH is 3. If the ph calculator answer is far away, check whether an input, unit, or mode changed.
Before copying
Review this common issue first: entering zero or negative concentration values.
Ref only. Verify values. Follow lab safety.
FAQ
Can pH be negative?
Yes, very concentrated strong acids can have pH below 0.
Can pH be above 14?
Yes, very concentrated strong bases can exceed 14 in some conditions.
Is temperature considered in this basic pH formula?
This basic form uses concentration directly and does not model temperature-dependent activity corrections.
Switch
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