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Time to Reach FV Goal

How long to accumulate a target amount through regular annual payments.

When to use: Use to find how long a savings plan takes to reach a financial goal.

Calculator

Formula

n=ln(FV×kPMT+1)ln(1+k)n = \frac{\ln\left(\frac{FV \times k}{PMT} + 1\right)}{\ln(1 + k)}

Variables

SymbolNameDescriptionUnit
nNumber of YearsTime to reach targetyears
FVFuture ValueSavings goal$
PMTPaymentAnnual savings amount$
kInterest RateAnnual return%

Real-Life Examples

Example 1: Retirement Timeline

Save $10,000/year at 8%. How long to reach $500,000?

Given

FV = 500,000PMT = 10,000k = 0.08

Step-by-Step

1.n = ln(500000 × 0.08/10000 + 1) / ln(1.08)
2.n = ln(5) / ln(1.08)
3.n = 1.6094 / 0.07696
4.n = 20.91 years
Result:20.91

It takes about 20.91 years to save $500,000.

Example 2: Down Payment Goal

Save $5,000/year at 4% to reach $40,000.

Given

FV = 40,000PMT = 5,000k = 0.04

Step-by-Step

1.n = ln(40000 × 0.04/5000 + 1) / ln(1.04)
2.n = ln(1.32) / ln(1.04)
3.n = 0.2776 / 0.03922
4.n = 7.08 years
Result:7.08

About 7 years to save $40,000 for a down payment.

Frequently Asked Questions

Enter the goal amount as FV, your annual savings as PMT, and expected return as k. The formula accounts for both your contributions and the compound growth of all previously deposited money.

This formula assumes you start from zero. If you have an existing balance, you need a combined formula that accounts for both the lump-sum growth of your current balance and the annuity growth of future contributions.

Higher contributions shorten the time to reach your goal significantly. Doubling your contribution more than halves the time because the larger deposits also earn more interest, creating a compounding advantage on top of the larger base.