how long will my savings last calculator

What this savings longevity calculator tells you

This tool answers a practical question: “If I stop working (or reduce work), how long will my savings support my lifestyle?” It models your balance month by month based on spending, outside income, investment return, and inflation. The output includes an estimated depletion date and timeline in years and months.

How the calculation works

At a high level, each month follows this sequence:

• Your portfolio grows (or shrinks) by the expected monthly return.
• Your net withdrawal is calculated as expenses minus other income.
• That withdrawal is taken from savings.
• Expenses and income are adjusted for their annual growth assumptions.

The loop repeats until your balance reaches your target ending balance (often $0), or until the simulation hits 100 years.

Inputs explained

• Current savings balance: Total assets available to fund your spending.
• Monthly expenses: Your average monthly outflow, including housing, food, healthcare, and discretionary costs.
• Monthly income: Social Security, pension, annuity, rent, part-time work, or other predictable inflows.
• Expected annual return: Long-term average return assumption for your portfolio.
• Annual inflation: How quickly your spending is likely to increase over time.
• Annual income growth: Cost-of-living increases for pensions or part-time income growth.
• Target ending balance: Amount you want to preserve for heirs, emergencies, or peace of mind.

Quick example

Suppose you have $500,000 in savings, spend $3,500 per month, receive $1,500 per month from outside income, expect a 4% annual return, and assume 2.5% inflation. Your initial draw from savings is $2,000 per month, but that draw grows over time as expenses rise. The calculator converts those assumptions into a month-by-month projection.

Why two people with the same savings can get very different results

1) Spending level dominates

A modest reduction in annual spending can add years to portfolio longevity. Small recurring costs often have a larger effect than one-time cuts.

2) Inflation compounds quietly

If your spending rises 3% per year, your required withdrawals increase meaningfully over a multi-decade retirement. Ignoring inflation can create false confidence.

3) Return assumptions matter

Using overly optimistic return assumptions can make a plan look safer than it is. Conservative estimates are usually better for planning.

4) Sequence of returns risk

Even with the same average return, poor returns early in retirement can hurt sustainability more than poor returns later.

Ways to make your savings last longer

• Delay retirement by even 1–3 years to reduce withdrawal years and add contributions.
• Reduce fixed monthly costs (housing, transportation, insurance) before cutting everything else.
• Create flexible spending rules: spend less after down market years.
• Diversify income streams (part-time work, consulting, rental income, annuities).
• Review tax strategy to reduce portfolio drag from avoidable taxes.
• Maintain a cash buffer so you are not forced to sell investments in a downturn.

Common planning mistakes

• Assuming inflation is zero.
• Forgetting healthcare and long-term care costs.
• Ignoring one-time large expenses (cars, home repairs, family support).
• Using a single “best case” return assumption.
• Not revisiting the plan yearly.

FAQ

Should I include Social Security and pension income?

Yes. Add reliable monthly inflows in the monthly income field. If they increase over time, use the annual income growth field.

What return should I use?

Use a conservative long-term estimate based on your asset mix and fees. Many planners stress-test multiple return assumptions rather than relying on one number.

Does this replace a full retirement plan?

No. This is a strong first-pass estimate. A full plan should include taxes, account types, required minimum distributions, healthcare variability, and scenario analysis.

Bottom line

A “how long will my savings last” calculator is one of the fastest ways to pressure-test your financial independence timeline. Run several scenarios, not just one. If the result is tight, adjust spending, timing, and income streams now—small changes today can create major flexibility later.