Many people guess blindly at how much money they’ll need in retirement. Though it can be tricky to come up with an accurate number, especially when retirement is many years away, you can use your current income as a guideline for how much to save. While there are always exceptions, generally speaking, you’ll be in pretty good shape if you put away 10% to 20% of your income for retirement, but inflation, return on investment, and Social Security should also be part of the equation.