Fidamen

Convert Calories to Joules – Energy Converter

This converter converts energy values between calories (small calorie, cal) and joules (J) using internationally accepted definitions. It also explains the dietary Calorie (capital C) which equals one kilocalorie (kcal).

The thermochemical calorie is the conventional reference for scientific work: 1 cal = 4.184 J. For food energy, the common label 'Calorie' (capital C) denotes 1 kilocalorie, equal to 1000 small calories or 4184 joules.

Updated Nov 8, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record d4d8b510b4dd • Reviewed by Fidamen Standards Committee

Interactive Converter

Convert between calorie and joule with precision rounding.

Quick reference table

CalorieJoule
CAL 1.00 cal4.18 J
CAL 5.00 cal20.92 J
CAL 10.00 cal41.84 J
CAL 25.00 cal104.6 J
CAL 50.00 cal209.2 J
CAL 100.00 cal418.4 J

Methodology

We apply the fixed, internationally recognized conversion factor for the thermochemical calorie: 1 small calorie (cal) = 4.184 joules (J). This factor is used by national measurement institutes and referenced in SI and metrology documentation.

For dietary energy, values labeled with a capital 'Calorie' (Cal) are treated as kilocalories (kcal). The converter supports converting either cal → J or kcal → J by applying the appropriate scale factor (×1 or ×1000) before multiplying by 4.184.

Where precision matters (laboratory measurements, instrumentation reports, regulatory declarations), follow calibration and uncertainty guidance from national metrology institutes and accredited test laboratories (for example, NIST guidance and ISO/IEC 17025 practices).

Worked examples

100 cal → 100 × 4.184 = 418.4 J

1 kcal (1 dietary Calorie) → 1 × 4184 = 4184 J

250 kcal (typical food serving) → 250 × 4184 = 1,046,000 J (≈ 1.046 MJ)

F.A.Q.

Is a dietary 'Calorie' the same as a small calorie?

No. Food labels use the term Calorie (capital C) to mean kilocalorie (kcal). 1 Calorie (food) = 1 kcal = 1000 small calories (cal) = 4184 J.

Which definition of 'calorie' does this converter use?

This converter uses the thermochemical calorie definition commonly adopted in chemistry and reference sources: 1 cal = 4.184 J. Older or context-specific definitions exist historically, but they are uncommon in modern scientific practice.

How many significant figures should I use when converting?

Match the precision of the original measurement. For instrument-derived values, report the conversion with the same number of significant figures and include uncertainty if required. For example, if you measure 123.4 cal (four significant figures), convert and report with comparable precision: 123.4 × 4.184 = 516.8 J (rounded appropriately).

Can I convert food energy into joules for recipes or lab calorimetry?

Yes. For recipes and general use, convert dietary Calories (kcal) to joules using 1 kcal = 4184 J. For calorimetry or research, ensure instruments are calibrated and account for measurement uncertainty per NIST and ISO/IEC 17025 guidance.

Are there measurement or calibration considerations I should be aware of?

Yes. Converting units is exact given the defined factor, but your input value may have measurement error. For precise work, follow calibration schedules and uncertainty reporting recommended by national metrology institutes and accredited lab standards (for example, NIST and ISO/IEC 17025).

Sources & citations

Further resources

Versioning & Change Control

Audit record (versions, QA runs, reviewer sign-off, and evidence).

Record ID: d4d8b510b4dd

What changed (latest)

v1.0.0 • 2025-11-08 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Public QA status

PASS — golden 25 + edge 120

Last run: 2026-01-23 • Run: golden-edge-2026-01-23

Engine

v1.0.0

Data

Baseline (no external datasets)

Content

v1.0.0

UI

v1.0.0

Governance

Last updated: Nov 8, 2025

Reviewed by: Fidamen Standards Committee (Review board)

Credentials: Internal QA

Risk level: low

Reviewer profile (entity)

Fidamen Standards Committee

Review board

Internal QA

Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person

Semantic versioning

  • MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
  • MINOR: New features or fields that do not change existing outputs for the same inputs.
  • PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.

Review protocol

  • Verify formulas and unit definitions against primary standards or datasets.
  • Run golden-case regression suite and edge-case suite.
  • Record reviewer sign-off with credentials and scope.
  • Document assumptions, limitations, and jurisdiction applicability.

Assumptions & limitations

  • Uses exact unit definitions from the Fidamen conversion library.
  • Internal calculations use double precision; display rounding follows the unit's configured decimal places.
  • Not a substitute for calibrated instruments in regulated contexts.
  • Jurisdiction-specific rules may require official guidance.

Change log

v1.0.0 • 2025-11-08 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: 0105e4accf58