Dividend safety metrics are used to analyze the probability that dividends will continue in the future. A few commons ones are the dividend payout ratio:
Dividend payout ratio = dividend / net income
The dividend coverage ratio:
Dividend coverage ratio = net income / dividend
And the FCFE Coverage Ratio:
FCFE coverage ratio = FCFE / (dividends + share repurchases)
Where (one option of FCFE calculation):
FCFE = cash flow from operations − FcInv + net borrowings
An FCFE coverage ratio that is much less than one indicates that a company has to finance dividends using cash reserves, which is not a sustainable practice.