Methodology

How the projections are calculated

Every figure here is a hypothetical illustration built from the numbers you enter. Nothing is uploaded, no account is required, and your inputs stay in your browser.

Four inputs, one result

  1. 01
    Current balance. The amount already saved in the retirement account you are tracking.
  2. 02
    Annual contribution. Your yearly deposit plus any employer match, measured against the match ceiling you set.
  3. 03
    Return assumption. A single yearly rate you choose, applied once per year to the running balance.
  4. 04
    Years to retirement. The gap between your current age and the target age you pick, such as 62, 65, or 67.

No risk scoring, no market timing, no outside data feeds. Change one input and the balance at retirement is recalculated in the browser.

Assumptions

What the projections take for granted

Every balance, income estimate and shortfall badge on this site comes from a short list of inputs you control. Change one, and the outcome moves. That is the point.

The defaults below describe a hypothetical scenario: a way to frame a planning conversation, not a forecast for your account or the market. No account is required, and anything you type stays in your browser.

Investment involves risk, including possible loss of principal. Past performance does not guarantee future results. This tool is educational and does not provide financial advice.

01Your contribution rate holds steady
The deferral percentage you enter continues unchanged each pay period, with no pause for a job change or unpaid leave.
02Employer match stops at the plan ceiling
The match applies only up to the stated cap, commonly 6% of pay. Anything you contribute above that line is treated as your own money.
03The annual return is a single flat number
Each year uses one average return rather than a sequence of strong and weak markets, so the path is smoother than real life tends to be.
04Inflation is applied every year
Projected income and spending amounts are shown in today's dollars, using one steady inflation rate for the whole horizon.
05Contributions stop at the age you enter
Retirement age acts as the end of saving and the start of withdrawals. Working longer is modeled as a separate scenario, not folded in.
06Withdrawals and longevity are estimates
Spending is held constant in real terms, and the planning horizon follows the life expectancy you choose rather than a fixed date.

See how these inputs are combined in the calculation steps, then try your own numbers on the scenario page.

Calculations

How each projection is built, step by step

Every figure on this site comes from the same seven steps. Nothing is read from a bank or brokerage account, and no input leaves your browser. You can follow the arithmetic by hand and compare it with the worked rows on the scenarios page.

  1. Start with today's balances

    You type in the current balance of each account you track. Cash savings, brokerage holdings, and retirement accounts are added into one starting figure.

  2. Add monthly contributions

    Your regular contribution is added once per month. An employer match counts only up to the match ceiling you enter, which is usually a percentage of pay.

  3. Apply a hypothetical growth rate

    The annual rate you choose is divided by twelve and applied to the running balance each month. Growth is therefore earned on prior growth as well as on new contributions.

  4. Count the months to your target age

    Years remaining until your chosen retirement age are multiplied by twelve. That product sets how many monthly cycles the projection runs.

  5. Project the balance

    The monthly loop runs to the end of the term and returns a single projected balance. Change one input and the whole loop repeats with the new value.

  6. Estimate monthly income

    The projected balance is multiplied by the withdrawal rate you select, which gives a hypothetical first-year monthly income before taxes.

  7. Compare the result with your goal

    That income estimate is measured against the monthly amount you said you need. A green badge marks a surplus, a rust badge marks a shortfall you may still need to close.

Projections are hypothetical and depend entirely on the inputs you enter. Investment involves risk, including possible loss of principal. Past performance does not guarantee future results. Read the full disclaimer before acting on any figure.

Disclaimers

What this tool does, and what it does not do

The Milestone Ledger is an educational planning resource. It helps you track contribution progress, compare hypothetical savings scenarios, and review retirement preparation milestones. It is not a financial advisor, a broker, or a tax preparer, and nothing here is a recommendation to buy, sell, or hold any investment.

Every projection you see is hypothetical. Results depend on the assumptions you enter, including contribution amounts, employer match, expected returns, and retirement age. Actual outcomes will differ. Investment involves risk, including possible loss of principal. Past performance does not guarantee future results.

Keep in mind

  • Figures are illustrative estimates, not quotes or guarantees.
  • Balances and income estimates ignore fees, taxes, and penalties your own accounts may apply.
  • Concentration, market timing, and withdrawal order could change a result substantially.
  • Rules for 401(k), IRA, and Social Security limits change over time and vary by situation.
  • No account is required. Your inputs stay in your browser and are not transmitted to us.

Review the methodology and assumptions used in the calculator, or read our full disclaimer. For advice about your own circumstances, speak with a licensed professional.