Titration Calculator

About the Titration Calculator

Titration is one of the most fundamental quantitative techniques in analytical chemistry. By gradually adding a solution of known concentration (the titrant) to a solution of unknown concentration (the analyte) until the reaction reaches its equivalence point, you can determine the exact concentration of the unknown. Acid-base titrations, redox titrations, complexometric titrations, and precipitation titrations each follow this same core principle.

The equivalence point is the theoretical point where stoichiometrically equivalent amounts of analyte and titrant have reacted. The end point is the experimentally observed point, detected by an indicator color change, pH jump, or other signal. Choosing the right indicator is critical: its transition range must bracket the equivalence point pH for acid-base titrations. Strong acid/strong base titrations reach pH 7 at equivalence (use bromothymol blue), while weak acid/strong base titrations give a basic equivalence point (use phenolphthalein).

This calculator computes the equivalence point volume and pH for acid-base and redox titrations, suggests an appropriate indicator, estimates the titration curve, and provides a comprehensive indicator reference table. Enter your analyte and titrant details and get a complete titration analysis ready for the lab bench.

When This Page Helps

Titration calculations involve multiple steps: finding equivalence volume, predicting equivalence pH, selecting an indicator, and understanding the curve shape. This calculator handles it all and prevents the common error of using the wrong indicator.

How to Use the Inputs

1. Select the titration type (strong acid–strong base, weak acid–strong base, etc.).
2. Enter the analyte concentration in moles per liter and its volume.
3. Enter the titrant concentration.
4. Set n-factors (1 for monoprotic, 2 for diprotic, etc.).
5. For weak acid/base titrations, enter the pKa.
6. Review the equivalence volume, pH, and suggested indicator.
7. Use the titration curve data to understand pH changes during the titration.

Example Calculation

Tips & Best Practices

• Rinse the burette with titrant solution before filling to avoid dilution error.
• Approach the equivalence point slowly — add titrant drop by drop near the end.
• For weak acids, the buffer region (pH ≈ pKa ± 1) shows slow pH change; the curve is steep only near equivalence.
• Record the burette reading to the nearest 0.05 mL for valid measurements.
• Run a rough titration first to find the approximate equivalence volume, then repeat accurately.

Types of Titrations

Acid-base titrations determine the concentration of an acid or base by neutralization. Redox titrations (e.g., permanganometry, iodometry) determine reducing or oxidizing agents. Complexometric titrations use EDTA to quantify metal ions. Precipitation titrations (Mohr, Volhard, Fajans) determine halide or silver ion concentrations. Each type uses different indicators and stoichiometric relationships.

Titration Curves

A titration curve plots pH (or potential for redox) against the volume of titrant added. Strong acid/strong base curves show a sharp vertical jump at equivalence. Weak acid/strong base curves have a shallower initial region (buffer zone) but still show a distinct jump at equivalence. The width of the jump determines which indicators will work. Polyprotic acid curves show multiple jumps.

Modern Titration Methods

While manual burette titrations are still taught, modern analytical labs often use automated titrators with potentiometric endpoint detection (pH electrode), amperometric detection (Karl Fischer water determination), or photometric detection. These instruments add titrant automatically and compute the equivalence point from the first or second derivative of the titration curve, achieving precision of ±0.01% relative standard deviation.

Frequently Asked Questions

• What is the difference between equivalence point and end point?

  The equivalence point is the theoretical stoichiometric point. The end point is the experimentally observed point (indicator color change). A good indicator has its end point as close as possible to the equivalence point.

• Why is the equivalence point pH not always 7?

  Only strong acid/strong base titrations reach pH 7 at equivalence. Weak acid/strong base gives a basic equivalence point because the conjugate base is formed. Weak base/strong acid gives an acidic equivalence point.

• How do I choose an indicator?

  Select an indicator whose color transition range includes the equivalence point pH. For example, phenolphthalein (8.2–10.0) works for weak acid/strong base, while methyl orange (3.1–4.4) works for strong acid/weak base.

• What is the half-equivalence point?

  At exactly half the equivalence volume, half the weak acid has been converted to conjugate base, so [HA] = [A⁻] and pH = pKa. This is used to determine pKa experimentally.

• Can I titrate a polyprotic acid?

  Yes. A diprotic acid like H₂SO₃ has two equivalence points. The titration curve shows two distinct pH jumps if the pKa values are sufficiently separated (by >3 units).

• What is a back titration?

  When the analyte reacts slowly or is insoluble, excess titrant is added first, then the unreacted excess is back-titrated with a second standard solution. The analyte amount = total added − excess titrated.