Calculator inputs
Use this planner to test how long savings may support withdrawals.
Example data table
Illustrative planning scenarios for testing the calculator.
| Scenario | Initial Savings | Annual Return | Years | Withdrawal | Contribution | Inflation | Planning Note |
|---|---|---|---|---|---|---|---|
| Starter retirement | $100,000 | 5.00% | 20 | $600 monthly | $0 yearly | 2.00% | Moderate draw with no added deposits. |
| Balanced income | $250,000 | 6.00% | 25 | $1,200 monthly | $3,000 yearly | 2.50% | Mixes withdrawals with ongoing support. |
| Aggressive draw | $150,000 | 4.50% | 15 | $1,500 monthly | $0 yearly | 3.00% | Higher shortfall risk across the term. |
| Capital preservation | $500,000 | 4.00% | 30 | $1,000 monthly | $6,000 yearly | 2.00% | Lower pressure with a stronger reserve. |
Formula used
1) Inflation-adjusted withdrawal per event
Withdrawaly = Base Withdrawal × (1 + Inflation Rate)(y − 1)
2) Monthly effective growth rate
Monthly Rate = (1 + Annual Rate ÷ Compounding Frequency)(Compounding Frequency ÷ 12) − 1
3) Balance update logic
Balancenext = Balance ± Contributions − Withdrawals + Interest
4) Interest for each month
Interest = Current Balance × Monthly Rate
5) Net withdrawal after estimated tax
Net Withdrawal = Gross Withdrawal × (1 − Tax Rate)
How to use this calculator
- Enter your current savings balance and expected annual return.
- Select how many years you want to project.
- Choose the compounding, withdrawal, and contribution frequencies.
- Enter the gross withdrawal amount for each event.
- Add inflation and estimated tax to make the plan more realistic.
- Optionally set a target ending balance to measure surplus or shortfall.
- Press Calculate savings plan to show the result above the form.
- Review the summary cards, chart, and yearly schedule, then export CSV or PDF if needed.
Frequently asked questions
1) What does this calculator estimate?
It projects how savings change while you withdraw money over time. It includes growth, optional contributions, inflation increases, timing choices, taxes, and the ending balance so you can judge sustainability more clearly.
2) Does withdrawal timing matter?
Yes. Beginning-of-period withdrawals reduce the balance before growth is applied, so the account usually finishes lower. End-of-period withdrawals let more money stay invested for longer.
3) Why add inflation adjustments?
A fixed withdrawal loses buying power over time. Inflation adjustment raises each year’s withdrawal by your chosen rate, helping the plan better reflect real spending needs.
4) Are the tax results exact?
No. The tax field is a simple estimate applied to each withdrawal. Actual tax outcomes depend on account type, jurisdiction, gains, deductions, and filing details.
5) What happens if the account runs short?
The schedule records the first shortfall month, shows partially funded withdrawals when needed, and continues the projection so you can test whether other inputs improve the result.
6) Can I model deposits while withdrawing?
Yes. Enter an annual contribution and select how often it is added. This helps model phased retirement, transition years, or hybrid saving and spending periods.
7) Which compounding choice should I use?
Pick the frequency that best matches your planning assumption or account behavior. Monthly is common for estimates, while annual or quarterly may suit simpler forecasts.
8) How should I interpret the result?
Review the ending balance, first shortfall, total net income, and yearly trend together. A plan can survive mathematically yet still feel fragile if the cushion stays small.