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About this tool
Convert calories to joules instantly. Free, bidirectional, and fully in-browser.
1 calorie equals 4.184 joules — enter any calorie value to convert it to joules instantly. This Calorie to Joule converter is a client-side tool: it applies a single multiplication (J = cal × 4.184) in your browser, updates the moment you type, and works in both directions — edit either field, or press swap, to convert joules back to calories. A reference table lists common calorie values already converted, and nothing you enter is sent to a server.
Open Calorie to Joule Converter on AltFTool — it loads instantly in your browser.
Type the value you want to convert into the Calorie field.
Read the equivalent in joules in the result field, and copy it if needed.
Use the decimal-places slider for more or less precision, or press swap to convert joules to calories.
The result updates as you type, and the swap button flips the conversion to joule → calorie without reloading.
The conversion uses the precise factor (J = cal × 4.184), so the number matches a manual calculation to the decimal places you choose.
A slider sets 0–10 decimal places, and very small or very large results switch to scientific notation instead of rounding to zero.
Everything runs locally in your browser — no upload, no account, no limit on conversions.
One calorie is 4.184 joules. Multiply the calorie value by 4.184 to convert. For example, 10 cal = 41.84 J.
J = cal × 4.184. This tool applies it automatically and shows a worked example: 10 cal = 41.84 J.
Yes. Press the swap button, or type into the joule field, and the tool converts joules to calories using the inverse of the same relationship.
It uses the standard energy and work definition (J = cal × 4.184), not a rounded approximation, so results are exact to the number of decimal places you select.
Yes. The converter is a browser-side script with no network calls: your values are never uploaded, and once the page has loaded it keeps working without a connection.
Add the Calorie to Joule Converter widget to your blog or website — free, responsive, no signup. Just keep the “Widget by AltFTool” credit link visible.
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