Monthly Savings Plan

Alexander Klar
January 2, 2017

The Idea

Create a small application including a GUI, that calculates and visualizes the results (including final balance) of a monthly savings plan.

The user can choose:

monthly amount to invest
duration (in years)
yearly returns in percent (interest, dividents, gains,…)
day on which the money is invested

Simple Example

30 years, 100 Euro, 1st of each month, annual return of 6 %:

paid <- 1200 # 12*100 Euro
oneYear <- 1200 + 6.5 * 6 * 100 / 100
totalBalance <- oneYear
savingsDF <- data.frame(year = 1, ammountPaid = paid, totalBalance = totalBalance )
for(i in 2:30){
  paid <- paid + 1200
  totalBalance <- totalBalance * (1 + 6/100) + oneYear
  savingsDF[i,] <- c(i, paid, totalBalance) }
head(savingsDF,2) # show first 2 entries

  year ammountPaid totalBalance
1    1        1200      1239.00
2    2        2400      2552.34

The Result

r <- barplot(savingsDF$totalBalance/1000, names.arg = savingsDF$year, main = "Total Balance in 1000 €", 
             xlab = "Years", ylim = c(0, totalBalance/800), col = "blue")
    lines(r, savingsDF$ammountPaid/1000, type = "h", col = "red", lwd = 4)

plot of chunk plot

Try it!

Here's the link: https://alklar.shinyapps.io/monthly_savings_plan/

If you have comments or questions, reach out to me.

The source code is available here: https://github.com/alklar/savings_plan