Companies, investors and others with an interest in a company often compare financial information from the same accounting period in two consecutive years to identify changes. This provides an appletoapples comparison of a company's growth or decline using the same information from the same time of year to avoid seasonal differences in a company's business. For example, you can calculate the change in revenue from the first quarter of one year to the first quarter of the next year. This is called the yearonyear, or yearoveryear, change, which is expressed as a percentage.

Determine the amount of an item from an accounting period in year one and the same accounting period in year two for which you want to calculate the yearonyear change. Years one and two can be any two consecutive years. For example, calculate the yearonyear change in $500,000 in secondquarter revenue in year one to $650,000 in secondquarter revenue in year two.

Subtract the amount of the item in year one from the amount of the item in year two. For example, subtract $500,000 from $650,000, which equals $150,000.

Divide your result by the amount of the item in year one. For example, divide $150,000 by $500,000, which equals 0.3.

Move the decimal two places to the right in your result and round to the tenths place, if necessary, to express the result as a percentage. For example, convert 0.3 to 30 percent. This is the yearonyear change in secondquarter revenue, which means the company's revenue grew 30 percent yearonyear.
Tips & Warnings
 If the amount of an item declines between years one and two, your result will be a negative percentage.
 You can also calculate yearonyear change in a company's nonfinancial numbers, such as number of subscribers or number of employees.
References
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