Watts to BTU Calculator

Convert watts to BTU/h (or reverse BTU/h to watts & kW) instantly—bidirectional thermal power conversion for heaters, AC capacity labels, and HVAC planning.

Calculator

Quick: watts → BTU/h. Advanced: reverse direction and switch W/kW.

Conversion direction

Power

Example: 1000 W heater or 5 kW electric load. Use kW for industrial ratings.

About this calculator

This watts to BTU calculator converts thermal power between W, kW, and BTU/h. It is not an energy converter (BTU ↔ kWh) and not a room-load sizer—use the HVAC capacity calculator for tons from floor area. Browse the power calculator hub.

Calculation Results

≈ 3,412 BTU/h (0.28 ton ref.)

1000 W · 1.000 kW · 3,412 BTU/h

Formula: BTU/h = W × 3.412141633

BTU/h is thermal capacity rate, not electrical input. Actual AC watts depend on EER/COP/SEER. 1 refrigeration ton ≈ 12,000 BTU/h (reference only).

Continue Your Calculation

Have thermal capacity in BTU/h or kW? Screen tons from floor area with HVAC capacity (not a substitute for Manual J).

HVAC capacity →

Watts to BTU/h quick reference

Uses IT factor 3.412141633. Click a row to load the calculator.

Input	Context	Result
	Space heater class	≈ 3,412 BTU/h
	Portable heater	≈ 5,118 BTU/h
	Electric heat / plant	≈ 17,061 BTU/h
	≈ 1 ton AC	≈ 3,517 W
	≈ 2 ton AC	≈ 7,034 W

Watts to BTU formula

Watts → BTU/h: BTU/h = W × 3.412141633

kW → BTU/h: BTU/h = kW × 3412.141633

BTU/h → watts: W = BTU/h ÷ 3.412141633

BTU/h — thermal power rate (capacity), not energy BTU
W / kW — SI power (here used as thermal-equivalent power)
1 ton (refrigeration) ≈ 12,000 BTU/h ≈ 3.517 kW

Example: 1000 × 3.412141633 ≈ 3412.14 BTU/h.

Need room tons from area? HVAC capacity calculator. Need line current from watts? Watts to Amps.

When to use which tool

Goal	Tool
Convert W/kW ↔ BTU/h (power)	This page
Estimate tons from floor area	HVAC Capacity
Convert watts ↔ amps	Watts to Amps
Convert amps ↔ kW	Amps to kW

Frequently Asked Questions

How do I convert watts to BTU/h?

Multiply watts by 3.412141633. Example: 1000 W ≈ 3412.14 BTU/h. For kW, multiply by 3412.141633.

How do I convert BTU/h to watts?

Divide BTU/h by 3.412141633. Example: 12,000 BTU/h ≈ 3516.85 W (≈ 3.517 kW).

Is BTU/h the same as electrical watts on an AC nameplate?

No. BTU/h is cooling/heating capacity. Electrical input depends on EER/COP/SEER. This calculator converts thermal power units only.

What is 5 kW in BTU/h?

5 × 3412.141633 ≈ 17,061 BTU/h. Use the 5 kW preset above.

Is this the same as BTU to kWh?

No. This page is power (BTU/h). Energy BTU ↔ kWh is a different conversion and is not handled here.