The average Brit spends almost a year (360 days) off sick throughout their working life, according to LV= research.
The survey of full-time workers, revealed stress and depression are two of the most common long-illnesses. Workers said they took an average of two and a half months (81 days) off to recover from these conditions.
LV= said assuming the average UK wage is £26,664, an employee suffering from stress and depression who only receives Statutory Sick Pay could lose up to £4,671 in wages- if they took the average amount of time off to recover.
Over 650,000 (2.9%) UK workers have been off with stress for more than a year during their career.
In the last three years one in 50 (435,800) workers have been off sick for more than a year, the research added.
LV= said the other most common and costly illnesses by recovery time and cost were bad back, with 57 days of absence, equal to an average loss in wages of £4,67.
Next employees took an average of 18 days to recover from severe migraines, equal to a financial loss of £849. Ear infections also cost employees £545 in 13 recovery days. Finally employees took around 10 days to recuperate from flu, costing £363.
However, the research revealed over a third (36%) of workers do not get sick pay cover from their employer. More than 7.8 million workers would only qualify for Statutory Sick Pay of £86.70 per week if they fell ill.
More than half (52%) of workers admitted to "being in the dark" as to what they would be entitled to. An additional quarter (26%) admitted they did not know how they would manage to make ends meet if they were without their regular income.
Over two-fifths (44%) of workers admitted they had returned to work before they were ready as they were concerned about the financial impact of taking any more time off.
Just one in ten has a policy in place that would provide them with a replacement income if they were unable to work.
Mark Jones, LV= head of protection said: "Often when we talk about workplace absence we look at the cost to businesses, however we wanted to highlight the impact that being off sick can have on an individual's finances and lifestyle. The fact that one in three would only receive Statutory Sick Pay indicates that many would be out of pocket and struggling financially, especially if they were off work for a long period of time."