What are the differences between the numerator and the denominator in the basic and diluted earnings per share calculations?

Diluted earnings per share is the amount of earnings for a reporting period that are available to each share of common stock outstanding during that reporting period, and to each share that would have been outstanding, assuming that common shares had been issued for all dilutive potential common stock outstanding during the period. An entity having more than common stock in its capital structure must present both basic and diluted earnings per share information for income from continuing operations and for net income. This information should appear on the face of the income statement.

The diluted earnings per share figure is only of importance when it diverges significantly from basic earnings per share. If so, it indicates that a company has issued a large number of warrants, options, or other convertible instruments that have the potential to sharply increase the number of common shares outstanding. If this is the case, investigate the strike prices at which the holders of the convertible instruments can buy common stock; the likelihood of conversion is quite high if the current market price is at or above the strike price. However, if the current market price is well below the strike price, there is no profit in buying common stock, in which case no one will buy stock, and the diluted earnings per share figure can be safely ignored.

The calculation of diluted earnings per share goes beyond the calculation of basic earnings per share to also include the effects of all dilutive potential common shares. As a result, you increase the number of shares outstanding by the weighted average number of additional common shares that would have been outstanding if all dilutive potential common stock had been converted to common stock. This dilutive change may also impact the profit or loss in the numerator of the earnings per share calculation. You calculate diluted earnings per share as follows:

Profit or loss attributable to common equity holders of the parent entity + Convertible preferred dividends + After-tax interest on convertible debt

Weighted average number of common shares outstanding during the period, plus all dilutive potential common stock

This calculation is further split into the profit or loss from continuing operations attributable to the parent entity, and total profit or loss attributable to the parent entity.