# Power Conversion Calculator

## Calculator Use

Convert among units of power and heat flow.

- (IT) = International Table
- (th) = Thermochemical

## How to Convert Units of Power and Heat Flow

Conversions are performed by using a conversion factor. By knowing the conversion factor, converting between units can become a simple multiplication problem:

**S * C = E**

Where **S** is our starting value, **C** is our conversion factor, and
**E** is our end converted result.

To simply convert from any unit into W, for example, from 50 BTU/h, just
* multiply by* the value in the right column in the table below.

50 BTU/h * 0.2930711 [ (W) / (BTU/h) ] = 14.653555 W

To convert from W into units in the left column
* divide by* the value in the right column or, multiply by the reciprocal, 1/x.

14.653555 W / 0.2930711 [ (W) / (BTU/h) ] = 50 BTU/h

To convert among any units in the left column, say from A to B, you can multiply by the factor for A to convert A into W then divide by the factor for B to convert out of W. Or, you can find the single factor you need by dividing the A factor by the B factor.

For example, to convert from BTU/h (th) to cal/s (th) you would multiply by 0.2928751 then divide by 4.184. Or, multiply by 0.2928751/4.184 = 0.069998829. So, to convert directly from BTU/h (th) to cal/s (th) you multiply by 0.069998829.

## Table of Power and Heat Flow Conversions

Note that you must first complete the operations in the Multiply By column in order to have the correct factor. For example, converting calorie per hour (IT) to watts, 4.1868/60/60 is 4.1868 divided by 60, divided by 60 which is equal to 0.001163. They were left in this form so that you could calculate a more accurate conversion factor.

Unit

Symbol

(W)

( W

^{}/ Unit )

_{IT}/h

_{IT}/min

_{IT}/s

_{IT}/h

_{IT}/min

_{IT}/sec

_{th}/h

_{th}/min

_{th}/s

_{th}/h

_{th}/min

_{th}/s

## References

The National Institute of Standards and Technology (NIST) -
*The NIST Guide for the use of the International System of Units* - Appendix B, subsections
B.8 Factors for Units Listed Alphabetically and
B.9 Factors for units listed by kind of quantity or field of science.

Lide, David R., Daniel (Editor-in-Chief).
*CRC Handbook of Chemistry and Physics, 89th Edition* New York, NY: CRC Press, p. 1-28, 2008.

Wikipedia contributors. "Conversion of units" Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, last visited 16 Nov. 2010.