Cernarus

Retirement Nest Egg Calculator

This calculator helps you estimate the lump sum you need at retirement to support a target annual income, and alternatively it projects how much your current savings plus future contributions may grow by retirement and what sustainable withdrawal that balance supports.

Choose the method that matches your intent: compute a target nest egg from desired income, or project your balance forward to check the income it would generate. Results are deterministic estimates and should be used for planning, not as a guarantee.

Updated Nov 18, 2025

Estimate the lump sum needed at retirement to sustainably generate your target annual income using a specified safe withdrawal rate and inflation adjustment between today and retirement.

Inputs

Results

Updates as you type

Required nest egg (gross)

$2,151,964.25

Recommended target (10% buffer)

$2,367,160.67

Required nest egg to cover taxes

$2,531,722.64

OutputValueUnit
Required nest egg (gross)$2,151,964.25USD
Recommended target (10% buffer)$2,367,160.67USD
Required nest egg to cover taxes$2,531,722.64USD
Primary result$2,151,964.25

Visualization

Methodology

Target nest egg uses an inflation adjustment to convert today's desired income into retirement-year dollars, then divides by a chosen safe withdrawal rate to estimate the principal needed to generate that income.

Projection computes future value using standard future-value formulas for lump sums and level annual contributions using an assumed nominal annual return, then multiplies the projected balance by the safe withdrawal rate to find a nominal sustainable annual withdrawal. Taxes are applied as a simple effective rate to report net income.

Calculations follow widely used financial math conventions; numerical functions such as pow() (exponentiation) are used for compounding. This tool is not a stochastic Monte Carlo simulator and does not model sequence-of-return risk explicitly.

Worked examples

Example 1: Age 45, retirement 67, desired income today $50,000, inflation 2.5%, SWR 4% → calculator inflates the $50k to retirement-year dollars and divides by 4% to give the required nest egg.

Example 2: Age 50, $200k current savings, $12k annual contributions, expected return 6% → calculator projects future balance at retirement and computes the annual sustainable withdrawal based on your chosen safe withdrawal rate.

Further resources

External guidance

Expert Q&A

Is the safe withdrawal rate guaranteed?

No. The safe withdrawal rate is an input assumption, not a promise. Historical studies provide guidance, but actual sustainable withdrawal depends on future returns, sequence-of-return risk, inflation, and your spending flexibility. Use conservative assumptions and consult a financial professional for tailored advice.

Does this tool account for market volatility or sequence-of-return risk?

No. This tool uses deterministic formulas and fixed annual return and inflation assumptions. It does not simulate return variability or sequence-of-return risk. For probabilistic analysis, consider additional tools or advisor-led modeling.

Why do you show a buffer?

A buffer (default 10%) is included as a simple risk allowance for unforeseen expenses, higher inflation, or lower returns. You can modify or ignore this buffer based on your risk tolerance.

How should I interpret after-tax estimates?

After-tax estimates apply a simple effective tax rate you enter. Actual taxes depend on account types, tax brackets, and timing. This is a planning estimate only.

What are the key limitations?

Deterministic projections assume constant nominal returns and inflation, do not model taxes in detail, fees, or pension/benefit interactions, and exclude behavioral responses to market changes. Use results for high-level planning and verify with professionals.

Sources & citations