Project a future savings balance, solve the month-end deposit needed for a goal, or calculate time to goal with an explicit 40-year not-reached result.
A quick decision brief for this specific tool
Mode, initial deposit, month-end deposit or positive savings goal, fixed nominal annual rate, whole-year horizon where applicable, and optional inflation rate
Future balance, required monthly deposit, or months to goal; dollar reconciliation, purchasing-power context, rate sensitivity, and monthly/yearly schedules
Monthly interest at nominal annual rate divided by 12 followed by a month-end deposit; reverse mode solves the same cash-flow equation and time-to-goal searches an explicit 40-year horizon
Choose your path
Solve a savings plan in three directions—future balance, monthly deposit needed, or time to goal—using one explicit monthly timing and interest convention.
Estimate a future balance from an existing fund and monthly deposits.
Choose future balance, enter starting amount/deposit/rate/time, and review deposits versus interest.
Gets a reproducible balance and understands the result assumes a constant rate with end-of-month deposits.
Calculate the monthly amount needed for a dated goal.
Choose monthly needed, enter goal/date horizon/start/rate, and inspect the solved deposit plus ending reconciliation.
Knows when the starting balance already reaches the goal and does not receive a negative required deposit.
Estimate when a goal is reached and recognize an infeasible 40-year horizon.
Choose time to goal, edit goal/monthly deposit/rate, and inspect the exact month or explicit not-reached state.
No silent clamp or blank result obscures the selected horizon and assumptions.
This tool is part of these guided projects. Each project provides step-by-step instructions with checklists and all the tools you need in one place.
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Compare an amount across published 2000–2025 BLS CPI-U annual averages or model a clearly labeled constant-rate inflation scenario in either direction.
The nominal annual rate is divided by 12, interest is credited to the existing balance, and the recurring deposit is then added at month end.
Balance_m = Balance_(m−1) × (1 + annual rate ÷ 12) + month-end depositReverse mode solves the ordinary-annuity equation for the month-end deposit. If the starting balance alone exceeds the goal at the horizon, the required deposit is exactly zero.
PMT = (Goal − future value of initial deposit) × monthly rate ÷ ((1 + monthly rate)^months − 1)Time mode checks each month for up to 40 years. If the goal is still not reached, the interface says so and shows the 40-year balance. Optional inflation discounts nominal value into approximate current purchasing power.
Updated: August 2026
Building a 6-month emergency fund with an initial deposit and monthly contributions in a high-yield savings account.
→ Future value: $8,763.58; deposits: $8,200; interest: $563.58
Starting from $1,000 at a fixed 4% nominal annual rate, solve the month-end amount needed for a $10,000 goal.
→ Required month-end savings: $357.49; projected balance: $10,000
$1 with no further deposits and 0% interest cannot reach $1,000,000 within 40 years. The tool reports not reached and preserves the $1 horizon balance instead of returning blank.
Timing changes growth. This calculator consistently deposits at month end, so use the same convention when comparing another tool or account illustration.
Rates and prices change. Use the entries as sensitivity scenarios, update them with current account information, and keep nominal goals separate from today-dollar purchasing power.
Choose the question you actually need answered: future balance, required monthly savings, or time to a goal. Every mode uses the same month-end deposit convention and reconciles deposits plus interest to the displayed balance.