Fidamen

Convert Kilojoules to British Thermal Units - Energy Converter

Convert energy values from kilojoules (kJ) to British Thermal Units (BTU) for engineering, HVAC, scientific, and educational use. This tool uses internationally recognized constants to ensure traceable and reproducible results.

Results are presented with guidance on rounding, significant figures, and measurement uncertainty to help you choose an appropriate level of precision for estimates, lab records, or regulatory reporting.

Updated Nov 26, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record b8317aa8c3ba • Reviewed by Fidamen Standards Committee

Interactive Converter

Convert between kilojoule and btu with precision rounding.

Quick reference table

KilojouleBTU
1 kJBTU 1.05 BTU
5 kJBTU 5.27 BTU
10 kJBTU 10.54 BTU
25 kJBTU 26.36 BTU
50 kJBTU 52.72 BTU
100 kJBTU 105.44 BTU

Methodology

The converter performs a two-step unit transform based on SI definitions: kJ → J (multiply by 1,000) and J → BTU (divide by the BTU value expressed in joules). The BTU value used is taken from metrology references to ensure consistency with standards.

Source constants and definitions are aligned with national and international standards bodies. For measurement-grade work, follow calibration and uncertainty practices recommended by NIST and ISO.

Worked examples

Example 1: 5 kJ → 5 × 0.947817120313 ≈ 4.7390856 BTU (report as 4.739 BTU for 4 significant figures).

Example 2: 0.25 kJ → 0.25 × 0.947817120313 ≈ 0.23695428 BTU (report as 0.237 BTU for three significant digits).

F.A.Q.

What exact conversion factor does this tool use?

This converter uses the thermochemical relation where 1 kilojoule = 1,000 joules and 1 BTU = 1,055.05585262 joules, giving a combined factor of 1000 / 1055.05585262 ≈ 0.947817120313. These constants are traceable to national standards.

Are there multiple BTU definitions and which should I use?

Historically there are variant BTU definitions (for example, International Table vs thermochemical variants). For most engineering and regulatory contexts the thermochemical BTU (the value used here) is standard and traceable to metrology references. If your domain specifies a different BTU definition, apply that definition consistently and document it.

How should I choose precision and rounding?

Choose precision based on the application: 2–3 significant figures for high-level estimates, 4–6 for engineering calculations, and more if instruments/standards require it. Always propagate measurement uncertainty from instruments and calibrations rather than relying solely on numeric rounding.

Does this conversion account for instrument calibration or measurement uncertainty?

No — numeric unit conversion is exact given the chosen constants. For measured energy values, include instrument calibration data and uncertainty budgets following NIST/ISO guidance. Report converted values with associated measurement uncertainty where traceability is required.

Can I use these results for regulatory reporting?

Unit conversion itself is not regulatory authorization. For compliance or formal reporting, verify which unit definitions and uncertainty reporting conventions your regulator or standards body requires and ensure measurements and conversions are traceable to recognized standards such as NIST and BIPM.

Why does the converter use joules as the intermediate?

The joule is the SI base unit of energy. Converting via joules ensures consistency with SI-based constants and international standards, improving traceability and interoperability between datasets and instruments.

Sources & citations

Further resources

Versioning & Change Control

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

Record ID: b8317aa8c3ba

What changed (latest)

v1.0.0 • 2025-11-26 • 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 26, 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 • 2025-11-26 • 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: ad4be3de7889