Updated Environment & Weather

Air Quality Index (AQI) Calculator

Compute air quality using US AQI and European CAQI, convert PM2.5 to AQI and get clear health guidance. Enter raw pollutant concentrations or ready-made AQI values and see the overall category and color scale.

US EPA AQI European CAQI PM2.5 ↔ AQI Converter AQI Color & Health Guide

Interactive Air Quality Index (AQI) Calculator

Use the tabs to calculate US AQI from pollutant concentrations, combine AQI values from different sources, convert PM2.5 to AQI, estimate European CAQI and explore health guidance based on the AQI category.

Enter the latest 24-hour average for particulate matter and appropriate averaging periods for gases. The calculator applies standard US EPA breakpoint formulas to estimate individual pollutant AQIs and the overall US AQI.

Use this mode when your air quality device or API already reports pollutant-specific AQIs. The overall AQI is simply the highest of the individual AQIs, and the dominant pollutant is the one that produces it.

This quick converter uses the US EPA breakpoint table for PM2.5. When converting from AQI back to concentration, the result is an approximate value within the corresponding breakpoint band.

This simplified CAQI mode uses typical European breakpoints for urban background monitoring. The final CAQI is the maximum of the sub-indices for PM, NO₂ and ozone.

Use this tab to interpret any AQI value, whether it comes from this calculator, a monitoring network or a mobile app.

US AQI Color Scale

AQI range Category Color Typical guidance
0 – 50 Good Green Air quality is considered satisfactory; little or no risk.
51 – 100 Moderate Yellow Acceptable air quality, but some pollutants may be a concern for a very small number of unusually sensitive people.
101 – 150 Unhealthy for Sensitive Groups Orange Members of sensitive groups may experience health effects; the general public is not likely to be affected.
151 – 200 Unhealthy Red Everyone may begin to experience health effects; members of sensitive groups may experience more serious effects.
201 – 300 Very Unhealthy Purple Health alert: everyone may experience more serious health effects.
301 – 500 Hazardous Maroon Health warnings of emergency conditions; the entire population is more likely to be affected.

What Air Quality Index (AQI) Calculator Calculates

Use Air Quality Index (AQI) Calculator to compute air quality using US AQI and European CAQI, convert PM2.5 to AQI and get clear health guidance.

Related tools in this category are listed under Science Calculators.

Air Quality Index (AQI) Calculator Inputs

Air Quality Index (AQI) Calculator uses PM2. Follow any limit or format displayed beside that field.

Air Quality Index (AQI) Calculator Formula or Method

  • Applies the standard linear interpolation formula to compute a pollutant-specific AQI.

Reading Air Quality Index (AQI) Calculator Results

The results include Overall US AQI, Dominant pollutant, AQI category, Health guidance, PM2.

Alongside Air Quality Index (AQI) Calculator, use Humidity Ratio & Moist Air Properties Calculator to compute humidity ratio (ω), specific humidity, mixing ratio and full moist air properties from temperature, relative humidity and pressure.

For a different result from Air Quality Index (AQI) Calculator, Heat Index Calculator can estimate heat index (feels like temperature) from air temperature and humidity. Includes danger level, dehydration risk, and safe outdoor timing guidance.

Calculators Related to Air Quality Index (AQI) Calculator

After checking Air Quality Index (AQI) Calculator, use Humidity Calculator – Relative, Absolute, Dew Point & Heat Index to analyze humidity using four modes:Relative humidity, absolute humidity, dew point and heat index. When you need to estimate your yearly carbon footprint from home energy, transportation and lifestyle, use Carbon Emissions Calculator – Full Footprint & Offsets. Dew Point Calculator covers a separate task: calculate dew point from air temperature and relative humidity, find relative humidity from dew point, estimate vapor pressure and absolute humidity.

After checking Air Quality Index (AQI) Calculator, use Wind Chill Calculator to estimate feels like temperature from air temperature and wind speed, see frostbite risk time. When you need to calculate dew point spread (dew point depression), relative humidity and fog or condensation risk, use Dew Point Spread Calculator – Dew Point Depression & Fog Risk. Wind Speed Calculator – Converter, Beaufort Scale & Wind Chill covers a separate task: convert wind speed between m/s, km/h, mph and knots, compute speed from distance and time.

After checking Air Quality Index (AQI) Calculator, use Wind Speed to Beaufort Scale Calculator to convert wind speed into Beaufort force 0–12 and instantly see standard descriptions, sea conditions and effects on land.

Frequently Asked Questions About Air Quality Index (AQI) Calculator

It is used to compute air quality using US AQI and European CAQI, convert PM2.5 to AQI and get clear health guidance.

It uses PM2. Follow any limit or format displayed beside that field.

Air Quality Index (AQI) Calculator uses Applies the standard linear interpolation formula to compute a pollutant-specific AQI.

It returns Overall US AQI, Dominant pollutant, AQI category, Health guidance, PM2.