Calculadora de CO₂ por Respiração
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
CO₂/dia ≈ 200 L/pessoa ≈ 0,4 kg; árvores = CO₂_kg/ano ÷ 22
About this calculator
This calculator estimates the amount of carbon dioxide (CO₂) exhaled by a person per day, month, or year, and how many trees are needed to absorb that CO₂ over a year. Human respiration produces CO₂ as a natural byproduct of metabolism, and the calculation uses an average rate of 200 liters of CO₂ per person per day, equivalent to approximately 0.4 kg. For compensation, it assumes an adult tree absorbs about 22 kg of CO₂ per year, a typical value for reforestation species.
How to use: enter the number of people in the group and select the desired period (day, month, or year). The calculator shows the total CO₂ emitted by respiration and the number of trees needed to offset that emission in one year. For example, one person emits about 146 kg of CO₂ per year (0.4 kg/day × 365 days), requiring approximately 7 trees for compensation. The result helps visualize the individual and collective respiratory impact on the carbon cycle.
When to use: ideal for environmental educators, students, and curious individuals who want to understand the contribution of human respiration to CO₂ emissions. Also useful in carbon offset projects, such as calculating how many trees to plant to neutralize the respiration of a group at events, schools, or companies. Remember that respiration is part of the natural carbon cycle, but the calculation serves as an awareness tool about the importance of forests.
Cautions: the values are population averages and may vary with age, physical activity, and metabolism. Tree CO₂ absorption depends on species, age, climate, and soil; 22 kg/year is a conservative estimate for tropical trees. This calculator does not consider other emission sources (such as fossil fuels) and should not be used for precise carbon inventories. Use as an educational reference.
Frequently asked questions
Does human respiration actually contribute to global warming?
Respiration is part of the natural carbon cycle; the CO₂ exhaled was recently in the atmosphere via food. It is not considered an additional greenhouse gas source, unlike fossil fuel burning.
Why does the calculation use 0.4 kg of CO₂ per day?
This value is based on an average production of 200 liters of CO₂ per day per adult at rest. The density of CO₂ at 25°C and 1 atm is about 1.8 g/L, resulting in approximately 0.36 kg, rounded to 0.4 kg.
How many trees are needed to offset the respiration of a family of 4?
One person emits ~146 kg/year. Four people emit ~584 kg/year. Dividing by 22 kg/tree, about 27 trees are needed.
Can I use this calculator for a corporate carbon inventory?
No, because it only considers human respiration. Inventories must include emissions from energy, transportation, waste, etc. Refer to standards like the GHG Protocol.
Does the number of trees change if I select month or year?
Yes. The calculator converts the period to days and calculates total CO₂. Trees are always calculated for one year of absorption, regardless of the selected period.