Determining exactly what needs to be saved for retirement is tricky. Basically it is something that needs to be adjusted based on how things go (savings accumulated, saving rate, planned retirement date, investing returns, predicted investing returns, government policy, tax rates, etc.). The simple idea is start by saving 15% of salary by the time you are 30. Then adjust over time. If you start earlier maybe you can get by with 12%…
How Much to Save for Retirement is a very good report by the Boston College center for retirement research. They look at the percent of income replacement social security (for those in the USA) provides. This amount varies greatly depending on your income and retirement (date you start drawing social security payments).
Low earners ($20,000) that retire at 65 have 49% of income replaced by social security. Waiting only 2 years, to 67, the replacement amount increases to 55%. For medium earners ($50,000) 36% and 41% of income is replaced. And for high earners ($90,000) 30% an 34%.
Starting savings early make a huge difference. Starting retirement savings at age 25 requires about 1/3 the percentage of income be saved as starting at 45. So you can save for example 7% from age 25 to 70 or 18% from age 45 to 70. Retiring at 62 versus 70 also carries a cost of about 3 times as great savings required each year. So retiring at 62 would require an impossible 65% if you didn’t start saving until 45. But these numbers are affected by many things (the higher your income the less social security helps so the higher percentages you need to save and many other factors play a role).
Starting to save early is a huge key. Delaying retirement makes a big difference but it is not nearly as much in your control. You can plan on doing that but need to understand that you cannot assume you will get to set the date (either because finding a job you can do and pays what you wish is not easy or you are not healthy enough to work full time).
If you don’t have social security (those outside the USA – some countries have their versions but some don’t offer anything) you need to save more. A good strategy is to start saving for retirement in your twenties. As you get raises increase your percentage. So if you started at 6% (maybe 4% from you and a 2% match, but in any event 6% total) each time you get a raise increase your percentage 100 basis points (1 percentage point).
If you started at 27 at 6% and got a raise each year for 9 years you would then be at 15% by age 36. Then you could start looking at how you were going and make some guesstimates about the future. Maybe you could stabilize at 15% or maybe you could keep increasing the amount. If you can save more early (start at 8% or increase by 150 or 200% basis points a year) that is even better. Building up savings early provides a cushion for coping with negative shocks (being unemployed for a year, losing your job and having to take a new job earning 25% less, very bad decade of investing returns, etc.).
Investing wisely makes a big difference also. The key for retirement savings is safety first, especially as you move closer to retirement. But you need to think of investment safety as an overall portfolio. The safest portfolio is well balanced not a portfolio consisting of just an investment people think of as safe by itself.
Related: Retirement Planning, Investing Asset Considerations – Saving for Retirement Must Be a Personal Finance Priority – Investment Risk Matters Most as Part of a Portfolio, Rather than in Isolation