Fidamen

Convert Kilojoules to Electronvolts - Energy Converter

This tool converts energy values from kilojoules (kJ) to electronvolts (eV) using SI-traceable physical constants. The conversion relies on the fixed value of the elementary charge and the SI definition of the joule.

The conversion is exact in terms of the defined constants used: 1 kilojoule = 1000 joules, and 1 electronvolt is the energy gained by an electron passing through a potential difference of one volt. For practical work, we show the numeric factor and guidance on choosing significant figures based on measurement and computational limits.

Updated Nov 30, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record a2c19ebcb24a • Reviewed by Fidamen Standards Committee

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Methodology

We use the internationally adopted constants and SI definitions. The elementary charge (e) is taken from the International System of Units (SI) definitions and CODATA/NIST references to convert joules to electronvolts.

Conversion process: convert kilojoules to joules by multiplying by 1000, then divide by the joule-equivalent of one electronvolt (1 eV = 1.602176634e-19 J) to get eV. For high-precision work, carry at least 9–12 significant digits through intermediate calculations and round only at the final step.

Key takeaways

Use this converter for fast, SI-traceable transformations between kJ and eV. For metrology, calibration, or regulatory reporting ensure you document constants and rounding rules used.

When interoperability with instruments or standards bodies is required, reference the NIST/CODATA/BIPM values cited below and preserve sufficient significant digits to avoid round-off error in downstream calculations.

Worked examples

Example 1: 1 kJ = 1 × 1000 J = 1000 / 1.602176634e-19 eV ≈ 6.241509074e21 eV.

Example 2: 2.5 kJ → 2.5 × 6.241509074e21 eV ≈ 1.5603772685e22 eV (report with appropriate significant figures for your context).

F.A.Q.

What numeric factor does this converter use?

This converter uses 1 eV = 1.602176634e-19 J (exact by the SI definition of the elementary charge) and 1 kJ = 1000 J. Therefore 1 kJ = 6.241509074e21 eV (approximate numeric factor derived from exact constants).

How many significant figures should I keep?

Keep at least as many significant figures as your least-precise input or instrument. For laboratory and computational work, preserving 9–12 significant digits through intermediate steps prevents meaningful round-off error; round only for reporting.

Are these values traceable to standards bodies?

Yes. The conversion is based on SI definitions and internationally recommended constants maintained by NIST, CODATA, and BIPM. For formal traceability in calibration and compliance contexts, cite the same sources and record the version of the constants used.

Can I convert very large or small energies without overflow/underflow?

Numeric limits depend on your computing environment. Values near 1e308 may overflow double-precision floating point. For extremely large/small values, use arbitrary-precision libraries or scientific notation and document the numeric format used.

Does instrument calibration affect the conversion?

The mathematical conversion is independent of instrument calibration, but measurement uncertainty from instruments (calorimeters, spectrometers) must be propagated through the conversion. Record instrument calibration certificates and include uncertainty when reporting converted values.

When should I reference official standards?

Reference official standards for metrology, certification, or regulatory reporting. Use NIST, BIPM, or national metrology institute publications when traceability or auditability is required.

Sources & citations

Further resources

Versioning & Change Control

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

Record ID: a2c19ebcb24a

What changed (latest)

v1.0.0 • 2025-11-30 • 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 30, 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 • 2025-11-30 • 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: 3e2aafaf59a8