Heat Index Calculator

Heat Index Calculator helps you calculate the apparent "feels like" temperature from air temperature and humidity. Use this free browser-based calculator from XTRAW Tools to compare inputs, estimate results, and plan your next step.

How to Use the Heat Index Calculator

1. Enter the required calculator inputs shown in the form.
2. Review the environmental, water, solar, compost, recycling, fuel, temperature, humidity, or weather assumptions.
3. Run the calculator, then adjust one input at a time to compare scenarios or check your estimate.

What This Calculator Helps With

Calculate the apparent "feels like" temperature from air temperature and humidity. It is designed for students, weather watchers, outdoor users, homeowners, pilots in training, educators, event planners, and general weather reference users who want a fast browser-based estimate before relying on official calculators, utility bills, weather stations, climate data, professional reports, supplier guidance, or regulatory sources.

• Air Temperature: 95°F
• Relative Humidity: 60%

Common Uses

People use this calculator when they need a quick way to estimate apparent temperature, heat index, wind chill, and weather safety conditions.

• Health Estimate: Review apparent temperature, humidity, and weather-safety reference values for general education only, not for medical or emergency decisions.
• Measurement: Use environmental, water, weather, energy, emissions, garden, recycling, or fuel inputs to calculate a practical estimate.
• Project Planning: Plan conservation projects, garden watering, rainwater systems, solar scenarios, carbon offsets, recycling goals, or weather reference checks.

Formula or Method

Rothfusz regression: HI = −42.379 + 2.049T + 10.143R − 0.225TR − ... (8-term polynomial)

Example

Example inputs: Air Temperature: 95°F; Relative Humidity: 60%

Example result: Using the default inputs, the heat index is about 113.1°F.

Related Tools

• Dew Point Calculator
• Relative Humidity Calculator
• Wind Chill Calculator
• Temperature Conversion Calculator
• Cloud Base Calculator

Heat Index Calculator FAQ

Is the Heat Index Calculator free?

Yes. This calculator is free to use on XTRAW Tools.

Do I need to create an account?

No. XTRAW tools are designed for browser-based use without requiring an account.

Are the results exact?

Results may be estimates depending on the inputs, formula, rounding, assumptions, local conditions, factor sources, measurement method, and purpose of the calculator. Always verify important results before relying on them.

Disclaimer: This calculator is provided for general informational, educational, and convenience purposes only. It is not meteorological, aviation, medical, occupational-safety, emergency, legal, financial, or professional advice. Weather formulas, local observations, microclimates, station data, and real-world conditions can vary. Always verify important weather, aviation, heat-safety, cold-safety, and emergency decisions with qualified professionals, official forecasts, local authorities, and authoritative sources before relying on them.