Kilojoule to Calorie Converter
Convert kilojoules to calories instantly. Free, bidirectional, and fully in-browser.
About this tool
Kilojoule to Calorie Converter
Convert kilojoules to calories instantly. Free, bidirectional, and fully in-browser.
1 kilojoule equals 239.0057361 calories — enter any kilojoule value to convert it to calories instantly. This Kilojoule to Calorie converter is a client-side tool: it applies a single multiplication (cal = kJ × 239.0057361) in your browser, updates the moment you type, and works in both directions — edit either field, or press swap, to convert calories back to kilojoules. A reference table lists common kilojoule values already converted, and nothing you enter is sent to a server.
How to use Kilojoule to Calorie Converter
- 1
Open Kilojoule to Calorie Converter on AltFTool — it loads instantly in your browser.
- 2
Type the value you want to convert into the Kilojoule field.
- 3
Read the equivalent in calories in the result field, and copy it if needed.
- 4
Use the decimal-places slider for more or less precision, or press swap to convert calories to kilojoules.
Why use Kilojoule to Calorie Converter
Instant, both ways
The result updates as you type, and the swap button flips the conversion to calorie → kilojoule without reloading.
Exact Energy math
The conversion uses the precise factor (cal = kJ × 239.0057361), so the number matches a manual calculation to the decimal places you choose.
Adjustable precision
A slider sets 0–10 decimal places, and very small or very large results switch to scientific notation instead of rounding to zero.
Private and free
Everything runs locally in your browser — no upload, no account, no limit on conversions.
Common use cases
- Converting a kilojoule measurement to calories for a spec, listing, or report.
- Checking kilojoule↔calorie figures while comparing products, datasets, or documentation.
- Learning the kilojoule-to-calorie relationship from the worked formula and the common-value table.
Frequently asked questions
How many calories are in a kilojoule?
One kilojoule is 239.0057361 calories. Multiply the kilojoule value by 239.0057361 to convert. For example, 10 kJ = 2390.057361 cal.
What is the formula to convert kilojoules to calories?
cal = kJ × 239.0057361. This tool applies it automatically and shows a worked example: 10 kJ = 2390.057361 cal.
Can it convert calories back to kilojoules?
Yes. Press the swap button, or type into the calorie field, and the tool converts calories to kilojoules using the inverse of the same relationship.
Is the conversion accurate?
It uses the standard energy and work definition (cal = kJ × 239.0057361), not a rounded approximation, so results are exact to the number of decimal places you select.
Does this work offline and stay private?
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.
Embed this tool on your site
Add the Kilojoule to Calorie Converter widget to your blog or website — free, responsive, no signup. Just keep the “Widget by AltFTool” credit link visible.
<iframe src="https://www.altftool.com/embed/widget/kilojoules-to-calories-converter"
title="Kilojoule to Calorie Converter — free AltFTool widget"
width="100%" height="640" style="border:0;border-radius:12px;overflow:hidden"
loading="lazy" referrerpolicy="no-referrer-when-downgrade" allow="clipboard-write"></iframe>
<p style="font-size:12px;margin:4px 0 0">Widget by <a href="https://www.altftool.com/tools/all/kilojoules-to-calories-converter?utm_source=embed&utm_medium=widget" rel="nofollow">AltFTool — free online tools</a></p>