Knowing you want $6,000 a month in retirement is easy; knowing whether you are actually on track is the hard part. This comprehensive planner closes that gap in three moves. First it projects your savings forward: Current Savings compounding at your Expected Annual Return plus your Monthly Contribution growing alongside, over the years from your Current Age to Retirement Age. Then it inflates your Desired Monthly Income (Today's $) by the Inflation Rate to find what that lifestyle really costs at retirement. Finally it prices that income as a Required Retirement Corpus and compares it against your projection — the shortfall becomes your Required Additional Monthly Savings.

You are 40 with $100,000 saved, adding $1,500 monthly at 7%, targeting $6,000 a month in today's dollars at 67 with 3% inflation. Your savings project to about $1.28 million, but the inflated income need — roughly $13,300 a month — prices a corpus near $2.7 million. The monthly shortfall: about $1,900 more needed, or a later retirement, or higher returns.

That shortfall figure is the most actionable number in retirement planning. It converts anxiety into a to-do list.

With the pre-filled defaults — Current Age 40, Retirement Age 67, Life Expectancy 90, Current Savings $100,000, Monthly Contribution $1,500, Expected Annual Return 7%, Inflation Rate 3%, Desired Monthly Income (Today's $) $6,000 — the US Retirement Calculator returns Years to Retirement 27, Years in Retirement 23, Projected Savings at Retirement $1,962,095.58, Inflation-Adjusted Monthly Income Needed $13,327.73, Required Retirement Corpus $52,549,351.33, Required Additional Monthly Savings $156,133.51. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.