{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"retirement-savings"},"result":{"entity_type":"calculator","id":"retirement-savings","calculator_id":"retirement-savings","canonical_url":"https://tttkmbb.com/finance/retirement-savings","name":"Retirement Savings Calculator","title":"Retirement Savings Calculator – Projected Balance at Retirement, Inflation-Adjusted, with Monthly Contributions","category":"finance","category_name":"Finance","tool_name":"project_retirement_savings","featured_mcp_tool":false,"description":"Projects retirement savings from the current balance and a fixed monthly contribution compounded monthly at an assumed annual return until the retirement age, reports the result in today's money using an inflation rate, and the income it supports at a 4 % withdrawal rate.","use_when":"You want to estimate what your savings will grow to by retirement, how much of that is contributions versus growth, and what it is worth in today's purchasing power.","do_not_use_when":"You need the amount required to retire (use fire-number), how long a balance lasts in retirement (use savings-withdrawal), or contributions that change over time.","inputs":[{"name":"current_age","label":"Current age","type":"number","unit":"years","required":true,"min":0,"max":100,"description":"Age today.","example":30},{"name":"retirement_age","label":"Retirement age","type":"number","unit":"years","required":true,"max":110,"exclusive_min":0,"description":"Planned retirement age; must exceed current_age.","example":65},{"name":"current_savings","label":"Current savings","type":"number","required":false,"default":0,"min":0,"max":1000000000000,"description":"Retirement balance today.","example":50000},{"name":"monthly_contribution","label":"Monthly contribution","type":"number","required":false,"default":0,"min":0,"max":1000000000,"description":"Amount added at the end of every month (including any employer match).","example":500},{"name":"annual_return_percent","label":"Annual return","type":"number","unit":"%","required":false,"default":7,"min":-50,"max":50,"description":"Expected nominal annual return in percent, compounded monthly.","example":7},{"name":"annual_inflation_percent","label":"Inflation","type":"number","unit":"%","required":false,"default":2.5,"min":-10,"max":30,"description":"Assumed annual inflation used to express the result in today's money.","example":2.5}],"outputs":[{"name":"years_to_retirement","label":"Years to retirement","type":"number","unit":"years","decimals":2,"description":"retirement_age − current_age."},{"name":"balance_at_retirement","label":"Balance at retirement (nominal)","type":"number","decimals":2,"description":"Projected balance in future currency."},{"name":"balance_in_todays_money","label":"Balance in today's money","type":"number","decimals":2,"description":"balance_at_retirement / (1 + inflation)^years."},{"name":"total_contributions","label":"Total contributions","type":"number","decimals":2,"description":"current_savings + monthly_contribution × months."},{"name":"investment_growth","label":"Investment growth","type":"number","decimals":2,"description":"balance_at_retirement − total_contributions."},{"name":"annual_income_at_4_percent","label":"Annual income at 4 % withdrawal","type":"number","decimals":2,"description":"0.04 × balance_at_retirement (nominal)."},{"name":"annual_income_in_todays_money","label":"Annual income in today's money","type":"number","decimals":2,"description":"0.04 × balance_in_todays_money."}],"input_schema":{"type":"object","properties":{"current_age":{"description":"Age today. Unit: years.","type":"number","minimum":0,"maximum":100,"examples":[30],"x-unit":"years"},"retirement_age":{"description":"Planned retirement age; must exceed current_age. Unit: years.","type":"number","maximum":110,"exclusiveMinimum":0,"examples":[65],"x-unit":"years"},"current_savings":{"description":"Retirement balance today.","type":"number","minimum":0,"maximum":1000000000000,"default":0,"examples":[50000]},"monthly_contribution":{"description":"Amount added at the end of every month (including any employer match).","type":"number","minimum":0,"maximum":1000000000,"default":0,"examples":[500]},"annual_return_percent":{"description":"Expected nominal annual return in percent, compounded monthly. Unit: %.","type":"number","minimum":-50,"maximum":50,"default":7,"examples":[7],"x-unit":"%"},"annual_inflation_percent":{"description":"Assumed annual inflation used to express the result in today's money. Unit: %.","type":"number","minimum":-10,"maximum":30,"default":2.5,"examples":[2.5],"x-unit":"%"}},"additionalProperties":false,"required":["current_age","retirement_age"]},"output_schema":{"type":"object","properties":{"years_to_retirement":{"description":"retirement_age − current_age. Unit: years.","type":"number","x-unit":"years"},"balance_at_retirement":{"description":"Projected balance in future currency.","type":"number"},"balance_in_todays_money":{"description":"balance_at_retirement / (1 + inflation)^years.","type":"number"},"total_contributions":{"description":"current_savings + monthly_contribution × months.","type":"number"},"investment_growth":{"description":"balance_at_retirement − total_contributions.","type":"number"},"annual_income_at_4_percent":{"description":"0.04 × balance_at_retirement (nominal).","type":"number"},"annual_income_in_todays_money":{"description":"0.04 × balance_in_todays_money.","type":"number"}}},"formula":"i = annual_return_percent/1200; m = 12 × (retirement_age − current_age); balance = current_savings × (1 + i)^m + monthly_contribution × ((1 + i)^m − 1) / i; todays_money = balance / (1 + inflation/100)^years; income = 0.04 × balance","method":"Constant return, constant contribution, end-of-month deposits, no taxes or fees. Real returns vary; the 4 % withdrawal figure is the Trinity-study rule of thumb for a 30-year retirement, not a guarantee.","sources":[{"name":"Investopedia – Future Value (FV): Formula and Calculation","url":"https://www.investopedia.com/terms/f/futurevalue.asp","type":"reference","retrieved_at":"2026-09-24"},{"name":"Wikipedia – Trinity study (safe withdrawal rates)","url":"https://en.wikipedia.org/wiki/Trinity_study","type":"reference","retrieved_at":"2026-09-24"},{"name":"Wikipedia – Time value of money","url":"https://en.wikipedia.org/wiki/Time_value_of_money","type":"reference","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"Age 30 to 65, 50,000 saved, 500/month, 7 %, 2.5 % inflation","inputs":{"current_age":30,"retirement_age":65,"current_savings":50000,"monthly_contribution":500,"annual_return_percent":7,"annual_inflation_percent":2.5},"expected":{"years_to_retirement":35,"balance_at_retirement":1475834.89,"balance_in_todays_money":621874.12,"total_contributions":260000,"investment_growth":1215834.89,"annual_income_at_4_percent":59033.4,"annual_income_in_todays_money":24874.96},"url":"https://tttkmbb.com/api/v1/calculate/retirement-savings?current_age=30&retirement_age=65&current_savings=50000&monthly_contribution=500&annual_return_percent=7&annual_inflation_percent=2.5"},{"name":"Age 45 to 67, 200,000 saved, 1,000/month, 6 %, 3 % inflation","inputs":{"current_age":45,"retirement_age":67,"current_savings":200000,"monthly_contribution":1000,"annual_return_percent":6,"annual_inflation_percent":3},"expected":{"years_to_retirement":22,"balance_at_retirement":1292451.73,"balance_in_todays_money":674520.87,"total_contributions":464000},"url":"https://tttkmbb.com/api/v1/calculate/retirement-savings?current_age=45&retirement_age=67&current_savings=200000&monthly_contribution=1000&annual_return_percent=6&annual_inflation_percent=3"}],"faq":[{"q":"Why is the inflation-adjusted balance so much lower?","a":"At 2.5 % inflation prices rise 2.37× over 35 years, so 1.48 million then buys what about 622,000 buys today. Plan with the today's-money figure."},{"q":"Should I enter a nominal or real return?","a":"Enter the nominal return and let the inflation input do the adjustment. Entering a real return with inflation set to 0 gives the same today's-money result."}],"tags":["retirement calculator","retirement savings","401k growth","nest egg","retirement projection","inflation adjusted"],"related":[{"calculator_id":"fire-number","reason":"How much you need to retire and when you reach it."},{"calculator_id":"compound-interest","reason":"Same growth arithmetic for any savings goal."},{"calculator_id":"inflation","reason":"Purchasing power of a future amount."}],"links":{"html":"https://tttkmbb.com/finance/retirement-savings","markdown":"https://tttkmbb.com/finance/retirement-savings.md","json":"https://tttkmbb.com/finance/retirement-savings.json","api":"https://tttkmbb.com/api/v1/calculate/retirement-savings","schema":"https://tttkmbb.com/api/v1/calculators/retirement-savings","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T02:03:06Z"}