Water Alkalinity Calculator
Calculate alkalinity of water from titration results – expressed in ppm as CaCO₃ (milligrams per liter).
Enter Titration Data
Formula: Alkalinity (ppm as CaCO₃) = (Acid mL × N × 50,000) ÷ Sample mL
Result
Typical Alkalinity Ranges
- 0 – 50 ppm: Soft, corrosive risk
- 50 – 150 ppm: Ideal for drinking
- 150 – 300 ppm: Hard water, scaling risk
- >300 ppm: Very high – treatment recommended
What is Water Alkalinity?
Water alkalinity represents the ability of water to neutralize acids. It is mainly determined by dissolved carbonate (CO₃²⁻), bicarbonate (HCO₃⁻), and sometimes hydroxide (OH⁻) ions. The most common reporting unit is ppm as CaCO₃ (mg/L as calcium carbonate).
Why is alkalinity important?
- Prevents sudden pH changes (buffers water)
- Protects water pipes and fixtures from corrosion
- Maintains stable water chemistry in aquariums
- Important for safe drinking water and boiler systems
Ideal Alkalinity Levels
Most guidelines recommend 50 – 150 ppm for drinking water. Very low values cause corrosion, while very high values cause scale buildup.
How this calculator works
You simply enter:
- Volume of acid used for titration
- Normality of acid
- Sample volume
Alkalinity = (Acid mL × Acid Normality × 50,000) ÷ Sample mL
This formula automatically converts units to ppm as CaCO₃ without additional calculation.