Convert Watt-Hours to Therms

Convert Watt-Hours (Wh) to Therms (thm) instantly and accurately.

Conversion Formula

thm = Wh × 3.412141633e-5

About Watt-Hours

A watt-hour (Wh) is the energy delivered by 1 watt for one hour - exactly 3,600 J. It is the practical unit for small-scale electrical energy: a 10,000 mAh 5 V power bank stores 50 Wh; a laptop battery holds 50-90 Wh; a smartphone battery holds 10-15 Wh; an AA alkaline cell stores ~3 Wh. LED lamps labelled 9 W save 51 Wh/h over a 60 W incandescent. IATA dangerous-goods rules use Wh as the threshold for lithium batteries in aircraft: cells >20 Wh and batteries >100 Wh need special approval. 1 Wh = 3,600 J = 3.412 BTU.

About Therms

A therm is the US natural gas billing unit equal to exactly 100,000 BTU = 105,505,585.262 J ≈ 105.5 MJ. One CCF of average US pipeline gas contains ~1.02 therms. The EIA publishes residential gas prices in $/therm; spot prices at Henry Hub are in $/MMBTU (1 MMBTU = 10 therms). US households average 500-700 therms/year for space heating, water heating, and cooking. A 15 kW domestic boiler running 2 hours delivers ~1 therm of useful heat. 1 therm = 100,000 BTU = 105.506 MJ = 29.307 kWh = 25,200 kcal.

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