Fidamen

Convert Kilojoules to Therms - Energy Converter

Convert energy values between kilojoules (kJ) and therms (US) quickly and reliably. This tool uses established unit definitions (therm = 100,000 British thermal units; 1 BTU ≈ 1055.05585 J) aligned with national metrology references.

Use the converter for engineering estimates, energy-reporting reconciliation, or unit normalization when comparing fuel or heating quantities across datasets. Guidance below explains the exact relationship, recommended precision, and when to reference official standards for regulatory compliance.

Updated Nov 6, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 6ce0798b2acf • Reviewed by Fidamen Standards Committee

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Methodology

The conversion is derived from the chain: 1 therm (US) = 100,000 BTU and 1 BTU = 1055.05585 joules (as used in international metrology). Convert kilojoules to joules by multiplying by 1,000, then divide by the joule-equivalent of one therm.

For clarity and traceability we reference national metrology guidance and energy statistics agencies. When producing data for regulatory filing or contractual measurement, round only after verifying instrument uncertainty and any jurisdictional reporting rules.

F.A.Q.

What is the exact conversion factor used?

This converter uses 1 therm (US) = 100,000 BTU and 1 BTU = 1055.05585 J (therm ≈ 105,505,585 J, or ≈ 105,505.585 kJ). Therefore therms = kilojoules ÷ 105,505.585.

Are there different definitions of a therm?

Yes. The most common in U.S. energy reporting is the therm (US) defined via 100,000 BTU. Other regions or legacy sources may use slightly different conventions—always confirm which therm variant your dataset or contract specifies before converting.

How many significant figures should I report?

Match the number of significant figures to the measurement uncertainty of your source data. For meter-level energy meters or invoice-level numbers, 3–4 significant figures is common; for lab calorimetry use instrument uncertainty and traceable calibration to decide. Avoid false precision.

Can I use this for regulatory or tax reporting?

This tool provides a standards-aligned numeric conversion for convenience. For formal regulatory, tax, or compliance submissions, follow the specific agency guidance and reporting rules in your jurisdiction and cite the agency-prescribed unit definitions and rounding rules.

How do I account for measurement uncertainty and calibration?

Propagate instrument uncertainty through the conversion (apply relative uncertainty to the kJ value, then convert). Ensure instruments are calibrated to a traceable standard; consult NIST or your national metrology institute for calibration best practices and accredited labs for certificates.

Why do results sometimes differ slightly from other converters?

Differences come from the base constants used (BTU definition precision, J per BTU, rounding). We use widely accepted metrology values; if you need exact parity with another dataset, align on the same base constants and rounding rules.

Sources & citations

Further resources

Versioning & Change Control

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

Record ID: 6ce0798b2acf

What changed (latest)

v1.0.0 • 2025-11-06 • 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 6, 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 • 2025-11-06 • 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: a25ae4fc3778