People who retire at 67 need to have banked roughly eight times their annual salary to have adequate finances for their retirement, Fidelity Investments said Wednesday.

In order to reach that level by 67, younger workers need to have saved an amount equal to their annual salary by age 35, three times their annual salary by age 45, and five times their annual salary by age 55, said Fidelity, a Boston-based financial services company whose specialties include retirement savings products.

If people have amassed an amount equal to eight times their annual salary in their final year of work, they can likely count on replacing 85-percent of their annual income for a 25-year period, according to this calculus.

Fidelity cautioned that its guidance is strictly a rule of thumb. The savings and spending habits of people vary widely, and so it is hard to devise a one-size-fits-all solution.