Calendar Year The one-year period that begins on January 1 and ends on December 31, based on the commonly used Gregorian calendar. For individual and corporate taxation purposes, a calendar year will generally comprise all of the year's financial information used to calculate income tax payable. Investopedia Says: Most individuals and many companies use the calendar year as their fiscal year, or the one-year period on which their payable taxes are calculated. However, some companies choose to report their taxes based on a fiscal year (e.g. starting on April 1 and ending on March 31) to better conform to seasonality patterns or other accounting concerns applicable to their businesses. Related Terms: Accounting Method Accounting Period Fiscal Year - FY Spillover Dividend Tax Year Year |