pOH Calculator
pOH calculator
Solve pOH chemistry from any one value: [OH-], [H+], pOH, or pH. Includes full profile output with pKw control and a visual acidity scale.
Result
pOH = 3
strongly basic • pOH 3
Live profile
pH scale
[H+]
1.0000e-11 mol/L
[OH-]
1.0000e-3 mol/L
pH
11
pOH
3
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 basic. Formula set: pOH = -log10([OH-]), pH = pKw - pOH, [H+] = 10^-pH.
Formula
pOH = -log10([OH-]) Symbol legend
| Symbol | Meaning | Unit | Copy |
|---|---|---|---|
\mathrm{pOH} | Potential of hydroxide | pOH units | |
[\mathrm{OH}^-] | Hydroxide ion concentration | mol/L |
- Enter hydroxide concentration in mol/L.
- Compute base-10 logarithm.
- Apply negative sign to obtain pOH.
Example
Worked example: [OH-] = 1.0 x 10^-4 M
- 1 [OH-] = 0.0001
- 2 pOH = -log10(0.0001)
- 3 pOH = 4
The solution pOH is 4.
How
- Enter [OH-] concentration in mol/L.
- Check that concentration is positive.
- Read the pOH output.
Avoid
- Typing hydrogen-ion values in the hydroxide field.
- Using non-positive concentrations.
- Forgetting that pH + pOH is approximately 14 at 25 C.
Checks
Best fit
pOH Calculator is built for calculate poh from hydroxide concentration using poh = -log10([oh-]) for fast base chemistry calculations. If pOH Calculator does not match the input scope, compare the answer with a second method.
Input check
Check \mathrm{pOH} before calculating: it means potential of hydroxide and is measured in pOH units.
Sanity check
For pOH Calculator, use the worked example as a quick benchmark: The solution pOH is 4. If the poh calculator answer is far away, check whether an input, unit, or mode changed.
Before copying
Review this common issue first: typing hydrogen-ion values in the hydroxide field.
Ref only. Verify values. Follow lab safety.
FAQ
How is pOH related to pH?
At 25 C, pH + pOH is approximately 14.
Can I convert pOH to pH directly?
Yes, subtract pOH from 14 at 25 C as a common approximation.
Does this account for activity coefficients?
No, this is a concentration-based educational calculator.
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