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Respiratory Quotient Calculator

Calculate respiratory quotient from carbon dioxide produced and oxygen consumed.

Respiratory Quotient measurements

Enter your values, then calculate.

Result

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CategoryBiology
Inputs2
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How to calculate respiratory quotient

Respiratory quotient (RQ) is the ratio of carbon dioxide produced to oxygen consumed during metabolism — a value that indicates which fuel source (carbohydrate, fat, or protein) is primarily being metabolized.

How the calculation works

RQ = CO2 produced ÷ O2 consumed.

Example

400 mL CO2 produced against 400 mL O2 consumed: 400÷400 = 1.0.

Frequently asked questions

How is Result calculated?

Result = [COu2082 produced] ÷ [Ou2082 consumed].

Is the Respiratory Quotient Calculator free to use?

Yes — every calculator on Simple Calculator Tools is free, runs in your browser, and does not require an account.

Quick Insight

Respiratory Quotient Calculator

RQ = CO2 produced ÷ O2 consumed.

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Your personalized explanation

Calculate a result above and this guide will help you interpret it using this calculator's own formula and explanation.

Pro Tips for Respiratory Quotient

  1. An RQ of about 1.0 suggests primarily carbohydrate metabolism; around 0.7 suggests primarily fat metabolism; values in between suggest a mixed fuel source.
  2. RQ must be measured with both CO2 and O2 in the same volume units for the ratio to be meaningful.

Common Respiratory Quotient Mistakes to Avoid

  • Measuring CO2 and O2 in different units or under inconsistent conditions, which would produce a distorted, non-comparable RQ value.

When to Use This Calculator

Respiratory quotient (RQ) is the ratio of carbon dioxide produced to oxygen consumed during metabolism — a value that indicates which fuel source (carbohydrate, fat, or protein) is primarily being metabolized.

Content reviewed: August 2026 · Robert Threadgill
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