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Measurements & Conversions

kWh to Therms Calculator

Convert kilowatt-hours into therms, for reading a metric energy figure against a gas tariff priced per therm.

  • Answers as you type
  • Every formula cited
  • Calculated in your browser
SettingsSettings for this calculationUS
Market
Imperial · sales tax
The energy in kilowatt-hours.

Kilowatt-hours reach a gas question from two directions. A UK or European gas bill states consumption in kWh directly, so converting it to therms is a straight comparison. An appliance rating in kW is a rate rather than a quantity, and becomes kWh only once you multiply by the hours it runs — a 24 kW boiler firing for two hours has used 48 kWh, not 24.

Energy

17.06 therms

High confidence

1 kWh = 1 ÷ 29.3071 = 0.0341214 therms. Exact by definition. Thirty kWh to the therm is the mental version and runs about 2.4 per cent high.

Kilowatt-hours entered
500 kWh
Therms
17.06 therms
BTU
1,706,070.82 BTU
Then change the inputs to see how far the answer moves.

Show calculation logic

How this was calculated

Formula source(s)

  • 1 therm = 100,000 BTU (IT); 1 BTU (IT) = 1055.05585262 J (NIST SP 811, Appendix B)
  • NIST SP 811 — 1 kWh = 3.6 MJ exactly

Inputs used

Energy (kWh)
500

Intermediate steps

Kilowatt-hours entered
500 kWh
Therms
17.06 therms
BTU
1,706,070.82 BTU
Final result17.06 therms

Confidence note: 1 kWh = 1 ÷ 29.3071 = 0.0341214 therms. Exact by definition. Thirty kWh to the therm is the mental version and runs about 2.4 per cent high.

What this calculation does not cover

  • An energy conversion only. Turning therms into a fuel volume needs that fuel's calorific value, which differs between natural gas, propane and oil.

Add the equipment this sizes

This result is a specification — 17.06 therms — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.

Sources checked 2026-09-12 · v1.0.0

Regulatory standards & verification citations2
  1. 1 therm = 100,000 BTU (IT); 1 BTU (IT) = 1055.05585262 J (NIST SP 811, Appendix B)
  2. NIST SP 811 — 1 kWh = 3.6 MJ exactly
Cite this page

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

This direction is mostly comparison work — a metric consumption figure that has to be read against a tariff, a historical bill or a piece of American analysis still written in therms. It is also where a specific confusion lives, and the help text takes it head on: kilowatts and kilowatt-hours differ by a multiplication that people skip, and a boiler's 24 kW nameplate entered here answers a question nobody asked. Beyond the conversion the page carries BTU, because North American gas appliances are rated in BTU per hour and the step from a month's energy to an appliance's hourly rating is the one this figure is usually on the way to.

How to calculate kWh to therms in 2 steps

  1. Energy (kWh)The energy in kilowatt-hours.
  2. EnergyThe tool computes the energy from those figures and shows the formula, its sources, and a confidence rating alongside it.

kWh to Therms at common values

Page defaults, not your figures above.

Energy (kWh)Energy (therms)
501.71
1003.41
2006.82
50017.1
1,00034.1
2,00068.2
5,000171

Frequently asked questions

How many kWh make a therm?
29.3071, so a therm is roughly thirty kilowatt-hours. The rough figure is good for a mental estimate and about two and a half per cent high, which is enough to matter across a heating season's worth of gas.
Why would I need therms if my bill is in kWh?
To compare across a border or across time. US tariffs, older UK bills and much of the published literature on heating costs are all in therms, so putting a modern kWh figure back into therms is often the only way to line it up against the number you are comparing it with.
What is the BTU row for?
Appliance sizing. Gas equipment is rated in BTU per hour across North America, and knowing that a month's consumption was so many million BTU is what lets you judge whether an appliance's hourly rating is plausible for the load it served.
Does this work for propane or oil?
As an energy conversion, yes — a kilowatt-hour is a kilowatt-hour whatever produced it. As a fuel quantity, no: propane is sold by the gallon or the litre and oil likewise, and turning energy into a volume of either needs that fuel's own calorific value, which this page has not been given.
Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — a confirmed fix gets a permanent check of its own, so the same mistake cannot come back.