How It Works
This calculator works in 4 steps.
Pick the reagent
Select HCl, HNO₃, H₂SO₄, NaOH, KOH, or a custom acid or base.
Enter the stock
Type the molarity, or the % w/w and density for a concentrated reagent.
Enter the target and volume
Type the target molarity and the final volume.
Read the volumes and pH
The calculator returns stock volume, water volume, the add-acid-to-water order, and the strong acid or base pH estimate.
The Formula
The formula applies C₁V₁ = C₂V₂ and estimates pH from the hydrogen or hydroxide ion concentration.
V₁ = C₂ × V₂ / C₁pH = −log₁₀[H⁺] = −log₁₀(C × z)pH = 14 + log₁₀[OH⁻]- C₁ / C₂:
- Stock and target molarity
- z:
- Acidic protons released per molecule
- [H⁺] / [OH⁻]:
- Hydrogen and hydroxide ion concentration
0.1 M HCl diluted 100-fold becomes 0.001 M with pH 3. 0.1 M NaOH diluted 100-fold becomes 0.001 M with pH 11.
Conversion Table
The conversion table shows the estimated pH for 6 dilutions of a strong monoprotic acid (HCl) and a strong base (NaOH) at 25 °C (77 °F).
| Starting molarity | DF | Final molarity | pH (HCl) | pH (NaOH) |
|---|---|---|---|---|
| 0.1 M | 1 | 0.1 M | 1 | 13 |
| 0.1 M | 10 | 0.01 M | 2 | 12 |
| 0.1 M | 100 | 0.001 M | 3 | 11 |
| 0.1 M | 1,000 | 0.0001 M | 4 | 10 |
| 1 M | 10 | 0.1 M | 1 | 13 |
| 0.01 M | 10 | 0.001 M | 3 | 11 |
What Is the Acid/Base Dilution Calculator?
The Acid/Base Dilution Calculator is a tool that dilutes acids and bases using their stated concentration, density, and assay, and returns the stock volume, water volume, and estimated pH of the result. The pH estimate applies to strong monoprotic acids and strong monobasic bases above 10⁻⁶ M.
Diluting a strong acid 10-fold raises the pH by 1 unit: 0.1 M HCl at pH 1 becomes 0.01 M at pH 2. Concentrated acids release heat on dilution, so the calculator prints the safety order: add acid to water, never water to acid. Weak acids, such as acetic acid, follow a different pH curve, and the calculator labels their pH as outside the strong-acid estimate.
Common Uses
There are 5 main uses of this calculator.
Titrant preparation
Analysts make 0.1 M HCl and 0.1 M NaOH from concentrates.
pH adjustment stocks
Labs prepare 1 M and 5 M NaOH and HCl for pH adjustment.
Digestion acids
Analysts dilute nitric acid for sample digestion.
Cleaning and descaling
Facilities dilute acid cleaners to labeled strengths.
pH teaching
Instructors show the 1-unit pH shift per tenfold dilution.