--- title: "Hydroxide Ion Concentration Calculator | Chemistry Formula Calculator | XTRAW Tools" description: "Calculate [OH⁻] concentration from pOH or pH. Use this free browser-based chemistry calculator from XTRAW Tools for lab, classroom, and STEM estimates." url: "https://xtraw.com/calculators/science-calculators/hydroxide-ion-concentration-calculator" date: "2026-05-20T21:55:58+00:00" language: "en-GB" --- [Work Calculator](https://xtraw.com/calculators/science-calculators/work-calculator)[Acceleration Calculator](https://xtraw.com/calculators/science-calculators/acceleration-calculator) [![Hydroxide Ion Concentration Calculator from XTRAW Tools](https://xtraw.com/images/virtuemart/product/xtraw-hydroxide-ion-concentration-calculator-360x360.jpg)](https://xtraw.com/images/virtuemart/product/xtraw-hydroxide-ion-concentration-calculator-360x360.jpg "Hydroxide Ion Concentration Calculator from XTRAW Tools") new [Back to: Science Calculators](https://xtraw.com/calculators/science-calculators "Science Calculators") # Hydroxide Ion Concentration Calculator Calculate [OH⁻] concentration from pOH or pH. Use this free browser-based hydroxide ion concentration calculator from XTRAW Tools. **Hydroxide Ion Concentration Calculator** helps you calculate \[OH⁻\] concentration from pOH or pH. Use this free browser-based calculator from XTRAW Tools to compare inputs, estimate results, and plan your next step. ## How to Use the Hydroxide Ion Concentration Calculator 1. Enter the required calculator inputs shown in the form. 2. Review the chemistry, acid-base, titration, buffer, formula, decay, cell-potential, or reaction-rate assumptions. 3. Run the calculator, then adjust one input at a time to compare scenarios or check your estimate. ## What This Calculator Helps With Calculate \[OH⁻\] concentration from pOH or pH. It is designed for students, teachers, chemistry learners, lab users, healthcare reference users, STEM tutors, and anyone working with chemistry formulas who want a fast browser-based estimate before relying on a textbook, lab software, chemistry reference, professional source, or specialist. - Input: pOH - pOH: 5 - pH: 9 ## Common Uses People use this calculator when they need a quick way to estimate pH, pOH, hydrogen ion concentration, hydroxide ion concentration, acidity, or basicity. - **Math Solving:** Solve chemistry, pH, pOH, buffer, titration, formula, electrochemistry, decay, or reaction-rate equations from entered values. - **Measurement:** Measure ion concentration, buffer pH, titration concentration, freezing point change, molecular formula ratios, decay values, or cell potential. - **Health Estimate:** Review acid-base and chemistry reference values for general education only, not for clinical or medical decisions. - **Project Planning:** Plan lab estimates, solution preparation, STEM assignments, chemistry study workflows, or classroom problem-solving tasks. ## Formula or Method \[OH⁻\] = 10^(−pOH); pOH = 14 − pH ## Example **Example inputs:** Input: pOH; pOH: 5; pH: 9 **Example result:** Using the default pOH of 5, \[OH⁻\] is about 1.0000e-05 mol/L. ## Related Tools - [pH Calculator](https://xtraw.com/tools/ph-calculator) - [pOH Calculator](https://xtraw.com/tools/poh-calculator) - [Hydrogen Ion Concentration Calculator](https://xtraw.com/tools/hydrogen-ion-concentration-calculator) - [Henderson-Hasselbalch Calculator](https://xtraw.com/tools/henderson-hasselbalch-calculator) - [Buffer pH Calculator](https://xtraw.com/tools/buffer-ph-calculator) ## Hydroxide Ion Concentration Calculator FAQ ### Is the Hydroxide Ion Concentration Calculator free? Yes. This calculator is free to use on XTRAW Tools. ### Do I need to create an account? No. XTRAW tools are designed for browser-based use without requiring an account. ### Are the results exact? Results may be estimates depending on the inputs, formula, rounding, chemistry reference values, assumptions, or purpose of the calculator. Always verify important results before relying on them. **Disclaimer:** This calculator is provided for general informational, educational, and convenience purposes only. It is not medical, laboratory, chemical handling, safety, legal, financial, academic, regulatory, nuclear safety, electrochemical engineering, or professional advice. 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