What is "Compound Interest"?

Compound interest is when interest is calculated on both the initial principal and the accumulated interest from previous periods. This 'interest on interest' causes exponential growth over time. Albert Einstein reportedly called it the 'eighth wonder of the world' due to its powerful wealth-building effect.

Example: $10,000 at 7% compound interest for 30 years → $76,000 (7.6x the principal)

Kalkulator Bunga Majemuk

0%10%20%
1y25y50y
Used for the "this year vs last year" simulation.
Total Diinvestasikan
Rp 650.000.000
Rp 650,0 jt
Total Bunga yang Diperoleh
+
+Rp 854,3 jt
Jumlah Akhir 🚀
(Rp 1,5 M)

Grafik Pertumbuhan

You vs Average

Benchmark: U.S. long-term average return assumed at 7%

Final gap: +Rp 0

This Year vs Last Year

Compares one-year outcomes using current and last-year return assumptions.

End-of-year difference: +Rp 673.170
💰

Compound Interest Result

Rp 1.504.253.592

Estimated interest: Rp 854.253.592

Expected value after 20 years (7% annual return)

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Apa itu Bunga Majemuk?

Bunga majemuk adalah bunga yang dihitung pada modal awal dan bunga yang terakumulasi dari periode sebelumnya. Berbeda dengan bunga sederhana yang hanya dihitung pada jumlah pokok, bunga majemuk memungkinkan uang Anda tumbuh lebih cepat seiring waktu.

Rumus Bunga Majemuk

A = P(1 + r/n)nt

A = P(1 + r/n)^(nt) dimana A adalah jumlah akhir, P adalah pokok, r adalah tingkat bunga tahunan, n adalah jumlah kali bunga dimajemukkan per tahun, dan t adalah waktu dalam tahun.

Aturan 72

Aturan 72 adalah cara sederhana untuk memperkirakan berapa lama waktu yang dibutuhkan untuk investasi menjadi dua kali lipat. Bagi 72 dengan tingkat pengembalian tahunan Anda untuk mendapatkan jumlah tahun yang kira-kira. Misalnya, dengan pengembalian tahunan 6%, investasi Anda akan menjadi dua kali lipat dalam sekitar 72÷6=12 tahun.

At 7% return, your investment doubles in about 10.3 years.

How to Read the Comparison Features

  • "You vs Average": See whether your assumptions outperform or underperform a U.S. long-term baseline.
  • "This Year vs Last Year": Quantify how a rate change shifts your one-year ending value under the same contribution plan.
  • Rate and term sliders update charts in real time so you can test scenarios quickly.

Tips Bunga Majemuk

  • Mulai berinvestasi lebih awal untuk memaksimalkan pertumbuhan majemuk
  • Lakukan kontribusi secara teratur, bahkan jumlah kecil akan bertambah
  • Reinvestasikan pendapatan Anda untuk mempercepat pertumbuhan
  • Berpikir jangka panjang untuk hasil terbaik
Last updated: 2025-01

📝 How to Use

1

Enter Initial Investment

Input your starting principal amount.

💡 Starting small is okay - consistency matters!

2

Set Annual Return Rate

Enter expected annual return rate (%).

💡 Stock funds average 7-10%, savings 2-4%.

3

Choose Investment Period

Enter how many years you plan to invest.

💡 Compound effect accelerates after 10 years!

4

Add Monthly Deposits (Optional)

If you plan to add money monthly, enter the amount.

💡 Regular contributions maximize compound growth.

🎯 Who is this for?

Useful for various situations

👶

College Fund for Kids

Start when your child is born to comfortably cover tuition costs.

Long-termEducation
🏠

Down Payment Savings

Calculate how long it takes to save for your dream home.

HomeSavings
🧓

Retirement Planning

Starting in your 30s makes comfortable retirement possible.

PensionRetirement
💎

Investment Simulation

Compare expected returns from ETFs, funds, and savings accounts.

ComparisonETF
💡

Expert Tip

The key to compound interest is 'time'. If you start investing $300/month at 30, someone starting at 40 can't catch up even with $1,000/month. The best time to invest was 10 years ago. The second best time is now.

Warren Buffett's Investment Philosophy

❓ Frequently Asked Questions

How do I use the compound interest calculator?

Just enter your initial investment, annual return rate, and investment period. Optionally, you can add monthly contributions. The calculator shows your final amount, total interest, and yearly growth chart.

💡 Adding monthly deposits supercharges your compound growth!

What is the Rule of 72?

Divide 72 by your annual return rate to estimate how long it takes to double your money. For example, at 8% return: 72÷8=9 years to double your investment.

💡 Our calculator automatically shows you the Rule of 72 result!

What is the difference between simple and compound interest?

Simple interest applies only to principal, while compound interest applies to principal + accumulated interest. $10,000 at 5% for 20 years: simple interest = $20,000, compound = $26,500. The longer you invest, the bigger the difference.

💡 This is why compound interest is called "interest on interest"!

What is a realistic annual return rate?

It varies by investment: Savings 2-4%, Bonds 3-5%, Stock ETFs 7-10%, Individual stocks vary widely. For long-term planning, 7% is a conservative and realistic estimate.

💡 Remember: higher returns usually mean higher risk!

How early should I start investing?

The earlier, the better! Starting at 25 with $200/month at 7% gives you ~$550,000 by 65. Starting at 35 with the same amount yields only ~$250,000. A 10-year difference makes more than 2x difference!

📌 Key Takeaways

  • Time is the most important factor in compound interest. Start early!
  • 📐Rule of 72: 72÷rate = years to double your money
  • 📈Monthly contributions maximize compound growth.
  • 🚀Long-term investing (10+ years) unlocks explosive compound growth.

📚 Panduan perhitungan lokal

Logika rumus

Menggunakan rumus publik untuk keuangan, pinjaman, rasio, dan konversi satuan.

Cakupan sumber

Mengacu pada standar publik dan praktik umum per negara.

Asumsi

Pajak, biaya, suku bunga, dan batas berbeda antar wilayah/lembaga.

Result Interpretation

Gunakan hasil ini sebagai skenario dasar. Sebelum memutuskan, bandingkan dengan penawaran nyata dan aturan pajak lokal.

Preset lokal

Mata uang: IDR

Satuan: metric

Model pajak: US payroll estimate

Catatan regulasi

Alat ini memakai preset regional untuk estimasi. Syarat nyata dan batas hukum dapat berbeda menurut lembaga dan aturan lokal.

Aksi yang disarankan

  • Bandingkan minimal 2-3 penyedia lokal sebelum final.
  • Cek ulang biaya, pajak, dan klausul pelunasan dipercepat secara tertulis.
  • Uji skenario stres dengan bunga +1-2% dan pendapatan turun.

Sebelum keputusan nyata, pastikan aturan terbaru di lembaga setempat.

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