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CO/CO2 ratio calculator

Type the flue gas readings from your analyser and get the combustion ratio, with last year’s readings alongside to see what has changed.

Today’s readings
Last year, optional

Combustion ratio

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  • Last year-
  • CO change-
  • CO₂ change-

Type CO in ppm and CO₂ in percent.

How it is worked out

Ratio = CO (ppm) ÷ (CO₂ (%) × 10,000), because 1 % is 10,000 ppm. For example, 200 ppm CO at 5.0 % CO₂ is 200 ÷ 50,000 = 0.0040.

The ratio is shown to four decimal places, as most analysers display it.

Good to know

Most analysers show the ratio themselves; this is a quick check and a way to compare with last year.

Acceptable values depend on the appliance. Use the manufacturer’s instructions and the industry action levels you work to. This tool does not decide whether an appliance is safe.

Everything is calculated in your browser. Nothing you type is sent or stored.

In Tickzu, readings, records, reminders and invoices sit with the customer and the appliance, ready for next year.

See Tickzu