Indoor CO2 Balance Calculator
Calculate well-mixed room CO₂ buildup with a constant entered source and ventilation flow.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Balance a constant-volume well-mixed tracer with entered source production and outdoor-air exchange.
Css=outside+10⁶×source m³/s/ventilation m³/s; C(t)=Css+(C0−Css)exp(−Qt/V)
Worked example
100 m³ room, 100 m³/h ventilation, 20 L/h CO₂ source and 420 ppm outside give a modeled steady concentration of 620 ppm.
Assumptions and input details
Constant source, constant ventilation and equal gas-volume reference conditions. No occupant emission standard, measurement interpretation, health threshold, infection risk or ventilation recommendation is inferred. CO₂ removal devices and spatial gradients are excluded.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
The 36 volume definitions distinguish US liquid, US dry and Imperial measures. Cups carry an explicit definition. Japanese shō is 2401/1331 L and a gō is one tenth of it; the explicitly labelled 180 mL rice cup is separate.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · UK Imperial definitions · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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