How conversion works
1 US therm = 100,000 BTU (IT)
So: BTU = therms × 100,000
And: therms = BTU ÷ 100,000
When using UK/EC therm, we first go through joules: therm_J ÷ BTU_J.
Why different therms and BTU?
Energy units were standardized at different times. Utilities may specify “therm (US)” or “therm (EC)” and use slightly different BTU bases. This calculator exposes those so you can match invoices, engineering handbooks, or government documentation.
FAQ
1. Which option should I pick for US natural gas billing?
Pick “US therm (100,000 BTU IT)” and “BTU (IT)”. That’s the convention used by many US suppliers.
2. What is kBTU?
kBTU = 1,000 BTU. It’s just a scaled version often used on energy reports; 1 therm = 100 kBTU.
3. Can I convert therms directly to kWh?
Not on this page, but the relationship is: 1 therm (US) ≈ 29.30011111 kWh. You can add that to your worksheet if needed.
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
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Formula (extracted text)
1 US therm = 100,000 BTU (IT) So: BTU = therms × 100,000 And: therms = BTU ÷ 100,000 When using UK/EC therm, we first go through joules: therm_J ÷ BTU_J.
Variables and units
- No variables provided in audit spec.
Sources (authoritative):
- NIST — Weights and measures — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/weights-and-measures - NIST — SI units — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/owm/metric-si/si-units
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.