Heat index calculator

Client

Approximate US heat index °F from temp and relative humidity.

99.7 °F

Nearby workflows on Toolcore

  • Wind chill calculator — US wind chill °F from temperature and mph—winter safety estimate. when units or numeric output should be checked on a related calculator.
  • Dew point calculator — Estimate dew point °F from dry-bulb temp and relative humidity. when units or numeric output should be checked on a related calculator.
  • Unit converter (length, temperature, weight) — Length (metric & US customary), temperature (°C, °F, K), and weight (mg to lb)—paste one value, see every column. when units or numeric output should be checked on a related calculator.
  • Percentage calculator — Percent of a value, ratio to percent, and percent change—no server round-trip. when units or numeric output should be checked on a related calculator.

About this tool

Feels-like temperature in humid heat—Fahrenheit and percent RH.

Common use cases

  • Heat index calculator for quick local checks without uploading data.
  • Copy results into tickets, docs, or classroom notes.

Common mistakes to avoid

  • Unexpected input shape

    See the intro and how-to notes for accepted formats.

FAQ

Is processing local?

Yes—this runs entirely in your browser.

Agent prefill?

Open the page directly—multi-field inputs are not URL-prefilled.

More tools

Related utilities you can open in another tab—mostly client-side.