How to Calculate a Stock Conversion Ratio

by Diane Stevens ; Updated July 27, 2017
Conversion ratios determine the value of convertibles compared to the common stock.

Some companies issue bonds or preferred stock that is convertible, at some future time, to common stock. At time of issue, the conversion relationship is usually defined as either a ratio or a price. If defined as a price, the ratio can be calculated using the par value of the convertible security and the defined price of the common stock.

Calculating Conversion Ratio

Read the indenture -- the documents that define the terms of the convertible -- for either the conversion ratio or the conversion price. If the ratio is not specified, use the conversion price to calculate the conversion ratio. Divide the nominal value of the security by the conversion price. For instance, if the nominal value is $1,000 and the conversion price is $40, the conversion ratio is 25 or 25:1.

About the Author

Diane Stevens' professional experience started in 1970 with a computer programming position. Beginning in 1985, running her own business gave her extensive experience in personal and business finance. Her writing appears on Orbitz's Travel Blog and other websites. Stevens holds a Bachelor of Science in physics from the State University of New York at Albany.

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