Model different financial outcomes based on your inputs. Useful for visualizing potential savings, investment growth, or debt reduction scenarios.
Your projected financial outcome will appear here.
Understanding the Free Financial Scenario Planner
This calculator helps you project the future value of an investment or savings plan. It accounts for an initial sum, regular contributions, and an expected rate of return over a specified period. It's a versatile tool for financial planning, allowing you to explore various "what-if" scenarios.
The Math Behind the Calculator
The calculation is based on the future value of an annuity formula, combined with the compounding growth of the initial investment.
Let:
$FV$ = Future Value
$P$ = Initial Investment (Principal)
$C$ = Periodic Contribution
$r$ = Annual Growth Rate (as a decimal)
$n$ = Number of times contributions are made per year (derived from contributionFrequency)
$t$ = Number of years
The formula for the future value of a series of payments (annuity) is:
$FV_{annuity} = C \times \frac{((1 + \frac{r}{n})^{nt} – 1)}{(\frac{r}{n})}$
The formula for the future value of the initial investment compounded over time is:
$FV_{principal} = P \times (1 + r)^t$
The total Future Value ($FV_{total}$) is the sum of these two components:
$FV_{total} = FV_{principal} + FV_{annuity}$
Simplified Logic in Calculator:
Since contributions are often made monthly and growth is annual, the calculator simplifies this by assuming contributions are made at the end of each period specified by 'Contribution Frequency (Months)' and the annual growth rate is applied to the total balance at the end of each year. The calculation is done iteratively year by year for simplicity and clearer conceptual understanding.
Inputs Explained:
Initial Amount: The lump sum you start with.
Periodic Contribution: The amount you plan to add regularly.
Contribution Frequency (Months): How often you make contributions (e.g., 1 for monthly, 12 for annually).
Expected Annual Growth Rate (%): The average yearly percentage return you anticipate from your investments or savings.
Time Period (Years): How many years you plan to invest or save.
Use Cases:
Retirement Planning: Estimate how much your retirement savings might grow.
Savings Goals: Project the growth of funds for a down payment, education, or other major purchases.
Investment Projections: Visualize the potential long-term growth of stock market investments.
Debt Paydown (Reverse Scenario): While not its primary design, you could input savings and use a negative growth rate to estimate how long it might take to reach a certain savings target to pay off debt.
General Financial Literacy: Understand the power of compounding and consistent saving.
function calculateFinancialScenario() {
var initialInvestment = parseFloat(document.getElementById("initialInvestment").value);
var periodicContribution = parseFloat(document.getElementById("periodicContribution").value);
var contributionFrequency = parseInt(document.getElementById("contributionFrequency").value);
var annualGrowthRate = parseFloat(document.getElementById("annualGrowthRate").value) / 100; // Convert percentage to decimal
var timePeriod = parseInt(document.getElementById("timePeriod").value);
var resultDiv = document.getElementById("result");
// Input validation
if (isNaN(initialInvestment) || isNaN(periodicContribution) || isNaN(contributionFrequency) || isNaN(annualGrowthRate) || isNaN(timePeriod) ||
initialInvestment < 0 || periodicContribution < 0 || contributionFrequency <= 0 || timePeriod <= 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for all fields.";
resultDiv.style.color = "#dc3545"; // Red for error
return;
}
var currentBalance = initialInvestment;
var totalContributions = 0;
var contributionPerPeriod = periodicContribution; // Contribution amount remains constant
// Calculate contributions per year
var contributionsPerYear = 12 / contributionFrequency;
if (!Number.isInteger(contributionsPerYear)) {
// Handle cases where frequency doesn't divide evenly into a year,
// for simplicity, we'll round down and adjust contributions at year end.
// A more complex model could distribute partial contributions.
contributionsPerYear = Math.floor(12 / contributionFrequency);
}
var totalPeriodicContributionsMade = 0;
for (var year = 0; year < timePeriod; year++) {
var yearlyContributions = 0;
for (var i = 0; i < contributionsPerYear; i++) {
currentBalance += contributionPerPeriod;
yearlyContributions += contributionPerPeriod;
totalPeriodicContributionsMade += contributionPerPeriod;
}
// Apply annual growth rate to the balance after contributions for the year
currentBalance *= (1 + annualGrowthRate);
}
var finalFutureValue = currentBalance;
// Display result
resultDiv.innerHTML = "Projected Future Value: $" + finalFutureValue.toFixed(2);
resultDiv.style.color = "#004a99"; // Primary blue for result
}