Retirement Calculator

Before you calculate

Use this calculator when you want to compare one retirement scenario at a time and keep the active mode, ages, return, inflation, savings, target, and withdrawal assumptions visible. Use 401(k) for workplace contribution and match inputs, RMD for required distribution estimates, Annuity or Annuity Payout for product-style payout math, Investment or Savings for generic accumulation, and Future Value or Present Value for narrower time-value-of-money questions. Use SSA, IRS, DOL/EBSA, Investor.gov, SEC, FINRA, FCA, MoneyHelper, The Pensions Regulator, plan administrator, provider, prospectus, fee-disclosure, tax-authority, inflation-statistics, legal, or local regulator sources before making Social Security, retirement-plan, pension, tax, annuity, product, fee, inflation, legal, regulated-advice, or jurisdiction-specific claims.

Formula summary

The calculator first sets years to retirement as max(0, retirementAge - currentAge) and retirement years as max(0, lifeExpectancy - retirementAge). Retirement Need grows current income by incomeIncrease, multiplies it by retirementIncomePercent, subtracts otherMonthlyIncome * 12, floors the annual need at 0, discounts that annual need with a real annual return from investmentReturn and inflationRate, then projects currentSavings with a yearly income-savings loop using futureSavingsPercent. Savings Required grows currentSavings to retirement and solves an annual ordinary contribution needed to reach targetRetirementAmount; monthlySavingsNeeded is annualSavingsNeeded / 12, not a separate monthly-deposit solve. Withdrawal Amount rounds years to retirement into months, grows currentSavings monthly, adds monthlyContribution after each month's growth, adds annualContribution every 12th month, and estimates withdrawal capacity with a real monthly return. Money Last starts with amountHave, grows it with nominal monthly investmentReturn, subtracts the planned monthlyWithdrawal or remaining balance, counts whole months, and stops at 12000 months as a computational cap.

Worked example

Example: four retirement questions from the app fixtures

In Retirement Need mode, the default inputs model current age 35, retirement age 67, life expectancy 90, $85,000 current income, 3% income growth, 75% income replacement, $1,200 other monthly income, $120,000 current savings, 12% future savings, 6% return, and 3% inflation. The app reports Required at retirement = $2,485,143.11, Projected savings at retirement = $2,093,029.74, Shortfall or surplus = -$392,113.37, and Retirement years = 23. In Savings Required mode, a $1,000,000 target, $75,000 current savings, age 35 to 65, and 6% return solve Annual savings needed = $7,200.24 and Monthly savings needed = $600.02. In Withdrawal Amount mode, age 50 to 67, life expectancy 92, $250,000 current savings, no new contributions, 5% return, and 3% inflation project $583,879.71 and support Monthly withdrawal capacity = $2,453.44. In Money Last mode, $750,000 amount have, $4,000 monthly withdrawal, and 5% return last 366 months, or 30.5 years.

The examples show the calculator mechanics and mode differences. They are not benefit estimates, pension valuations, annuity quotes, tax answers, market forecasts, withdrawal recommendations, product comparisons, legal answers, or personalised retirement advice.

Assumptions

• Return, inflation, income growth, contribution, target, amount-have, withdrawal, age, and life-expectancy values are user-entered scenario assumptions. The calculator does not forecast markets, wages, inflation, benefits, tax law, plan rules, healthcare costs, fees, product terms, or lifespan.
• Different modes use different timing. Retirement Need projects yearly income-based saving; Savings Required solves an annual contribution and then divides by 12 for display; Withdrawal Amount uses monthly contributions after growth plus annual contributions every 12th month; Money Last uses a nominal monthly return and does not inflation-adjust the entered withdrawal.
• Package fixtures cover all four modes, and scoped internal independent comparator evidence covers savings-required annual outputs only. SSA sources are needed for Social Security claims; IRS and DOL/EBSA sources are needed for US retirement-plan rules; Investor.gov, SEC, FINRA, provider, prospectus, and fee-disclosure sources are needed for investment-product and fee claims; FCA, MoneyHelper, The Pensions Regulator, BLS, ONS, tax-authority, legal, and local regulator sources are needed before pension, annuity, inflation-statistic, tax, legal, regulated-advice, or jurisdiction-specific claims. Results are educational estimates, not financial, tax, legal, pension, benefits, investment, insurance, lending, regulated-product, or personalised advice.

Common mistakes to avoid

• Treating one retirement result as a forecast or complete plan. The output is only the result of the selected fixed assumptions.
• Comparing modes without noticing unused outputs or the annual-savings display convention. Several outputs stay at $0 or 0 when they do not apply, and the app solves annualSavingsNeeded before displaying monthlySavingsNeeded by dividing that annual amount by 12.
• Using the result as a Social Security estimate, pension valuation, annuity quote, tax calculation, product comparison, inflation forecast, legal answer, or personal recommendation.

Methodology and sources

This calculator is an original implementation based on documented formulas, app-specific assumptions, deterministic fixtures, edge cases, rounding policy tests, and internal validation. It is not copied from a single source.

Outputs are checked with deterministic fixtures, edge cases, rounding policy tests, and internal independent comparator checks where overlapping outputs are available. The result remains an educational estimate, not a quote, approval, tax answer, or personalised advice.

Formula version 2026.05.22-generic-retirement-planning-modes. The version marks the calculation logic and validation fixture set used for this estimate.

• SSA sources should be used before copy discusses Social Security benefit ages, eligibility, replacement rates, benefit estimates, or payment amounts.
• IRS and DOL/EBSA sources should be used before copy discusses US retirement-plan contributions, distributions, account rules, tax treatment, participant rights, employer plans, or savings guidance.
• Investor.gov, SEC, FINRA, product documents, prospectuses, fee disclosures, and provider materials should be used before copy frames fixed return assumptions as real investment returns, product performance, fees, risk, diversification, guarantees, or regulated investment guidance.
• FCA, MoneyHelper, The Pensions Regulator, BLS, ONS, local statistics agencies, tax authorities, accounting standards, lender disclosures, and relevant local regulators should be used before adding pension, annuity, inflation-statistic, tax, legal, accounting, lending, regulated advice, or jurisdiction-specific claims.

Estimate only

The result is educational and is not financial, tax, legal, lending, investment, or regulated advice. Real provider terms, fees, rates, taxes, and personal circumstances can change the final answer.

Formula and help: read the full retirement calculator methodology notes.

Related reading

• Retirement planning with simple estimates
• How Calcs.finance validates calculator formulas
• Estimate limitations and not-advice disclaimer

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