Dissolved Oxygen Calculator

Dissolved oxygen (DO) saturation tells you how much oxygen water can hold — critical for assessing aquatic health, fish survival, and water quality. Enter your water temperature, barometric pressure, salinity, and elevation into the Dissolved Oxygen Calculator to find the DO Saturation Concentration in mg/L. Optionally add a measured DO reading to calculate your DO saturation percentage, along with pressure and salinity correction factors.

°C

Water temperature affects oxygen solubility

kPa

Atmospheric pressure at measurement location

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Salt content in parts per thousand (0 for freshwater)

m

Elevation above sea level (affects pressure)

mg/L

Your actual DO reading to calculate saturation %

Results

DO Saturation Concentration

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DO Saturation Percentage

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Pressure Correction Factor

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Salinity Correction Factor

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Frequently Asked Questions

What is dissolved oxygen and why is it important?

Dissolved oxygen (DO) is the amount of oxygen gas dissolved in water, typically measured in mg/L or ppm. It's critical for aquatic life survival and indicates water quality health.

How does temperature affect dissolved oxygen levels?

As water temperature increases, its ability to hold dissolved oxygen decreases. Cold water can hold more oxygen than warm water, which is why thermal pollution is harmful to aquatic ecosystems.

What is DO saturation percentage?

DO saturation percentage compares the actual dissolved oxygen concentration to the maximum possible concentration under current conditions. 100% means the water is fully saturated with oxygen.

How does salinity impact oxygen solubility?

Salt water holds less dissolved oxygen than freshwater. As salinity increases, the maximum oxygen concentration decreases, requiring correction factors in calculations.

Why does elevation matter for DO calculations?

Higher elevations have lower atmospheric pressure, which reduces oxygen solubility in water. This pressure difference must be accounted for in accurate DO calculations.

What are typical DO levels for healthy water bodies?

Healthy freshwater typically contains 7-11 mg/L of dissolved oxygen. Levels below 5 mg/L stress fish, and below 3 mg/L can cause fish kills. Ocean water averages 6-8 mg/L.

How accurate are calculated DO saturation values?

When using standard equations (like Benson-Krause), calculated values are typically accurate within ±0.1 mg/L under normal conditions, making them reliable for most applications.