Convert Kilojoules to Kilowatt Hours - Energy Converter
This converter translates energy values from kilojoules (kJ) to kilowatt-hours (kWh) using the International System of Units (SI) definitions. It applies the fixed, physics-based relationship between joules, watts, and seconds to produce exact conversions appropriate for engineering, laboratory, and regulatory workflows.
The tool is intended for quick, authoritative conversions and for use as a verification step when preparing energy inventories, lab reports, or performance calculations. For measurement-grade work, follow instrument calibration guidance and report results with appropriate significant figures and uncertainty.
Governance
Record f1d77e08069a • Reviewed by Fidamen Standards Committee
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Methodology
The conversion is derived from SI definitions: 1 watt equals 1 joule per second (1 W = 1 J/s). A kilowatt-hour is the energy delivered by 1 kilowatt acting for one hour: 1 kWh = 1000 W × 3600 s = 3,600,000 J.
Expressed in kilojoules, 1 kWh = 3,600 kJ. Therefore to convert kilojoules to kilowatt-hours, divide the kilojoule value by 3,600. This relationship is exact within the SI system and is documented by standards authorities.
For applied and regulatory use, record the number of significant figures supported by your measurement device and, where needed, include instrument calibration traceability (for example, NIST-traceable certificates) and uncertainty estimates in reports.
Worked examples
3600 kJ → 3600 ÷ 3600 = 1 kWh
9000 kJ → 9000 ÷ 3600 = 2.5 kWh
150 kJ → 150 ÷ 3600 ≈ 0.0416667 kWh (report with appropriate sig figs)
F.A.Q.
What is the exact conversion factor between kJ and kWh?
Exactly 1 kWh = 3,600 kJ, so use kWh = kJ / 3600.
How do I convert kilojoules per hour (kJ/h) to kilowatts (kW)?
Convert kJ/h to watts by noting 1 kJ = 1000 J and 1 hour = 3600 s. So 1 kJ/h = 1000 J / 3600 s ≈ 0.277777... W, which is 0.000277777... kW. For kJ/h → kW multiply by 0.0002777777778.
How many significant figures should I report?
Match the precision to the upstream measurement device and the purpose of the calculation. For engineering audits and instrument readings, report the same number of significant digits as the instrument supports and include uncertainty or calibration status when required by standards or regulatory guidance.
Does this conversion account for measurement uncertainty or meter efficiency?
No. This converter performs a fixed-unit arithmetic conversion only. For real-world energy measurements, account separately for meter accuracy, instrument calibration, measurement uncertainty, and any system losses or efficiencies.
Where should I cite the conversion in technical documents?
Cite an authoritative SI reference or standards guidance (for example, national metrology institutes or ISO standards) and include the conversion formula kWh = kJ ÷ 3600 in your methods section. If measurements are used for compliance, include calibration traceability and uncertainty statements.
Sources & citations
- NIST Special Publication 811 — Guide for the Use of the International System of Units (SI) — https://www.nist.gov/pml/special-publication-811
- NIST — Metric (SI) Units and Conversions — https://www.nist.gov/pml/weights-and-measures/metric-si
- U.S. Energy Information Administration — Energy Unit Conversions and Definitions — https://www.eia.gov/tools/faqs/faq.php?id=45&t=8
- ISO 80000 series — Quantities and units (overview) — https://www.iso.org/standard/30669.html
Further resources
Versioning & Change Control
Audit record (versions, QA runs, reviewer sign-off, and evidence).
Record ID: f1d77e08069aWhat changed (latest)
v1.0.0 • 2025-11-01 • 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
Versioning & Change Control
Audit record (versions, QA runs, reviewer sign-off, and evidence).
What changed (latest)
v1.0.0 • 2025-11-01 • 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 1, 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 • 2025-11-01 • 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: cc1e5f5655a5