An employee with an income of $50,000 at retirement will need to replace 81 percent of that amount each year to maintain his standard of living, according to the 2008 Replacement Ratio Study conducted by Aon Consulting and Georgia State University.

If an employer earns $150,000 at retirement, he will need to replace 84 percent of that income to sustain his standard of living.

But financial planners say that specific situations will dictate the most suitable figure.

The percentage of retirement income depends on such factors as the quality of the retirement lifestyle, length of retirement, final base salary, marital status, number of children in a household, investment returns, federal taxes, inflation rates, medical care expenses and others.

But some say replacement rates above 70 percent to maintain living standards in retirement is “conceptually flawed.” That’s what University of Wisconsin professors John Karl Scholz and Ananth Seshadri write in “What Replace Rates Should Households Use?”

In the 2009 paper, the authors concluded that the optimal replacement rates could be as low as 23 percent for single parents with several children and a negative late-in-career earnings shock (layoff or big salary decrease). For low-income, married households with a few children and a substantial positive late-in-career earnings shock, the rate can be as high as 240 percent. “Large number of factors will affect optimal target replacement rates,” they concluded.

The bottom line: People need to make detailed and accurate estimates of their retirement spending. This can be done on their own or through online retirement income calculators