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Compound Interest Calculator

Calculate how your investment grows over time with compound interest. See total amount, interest earned, and effective annual rate.

Written by CalcVault Editorial Team
₫
%
years

Fill in the fields above and click Calculate to see your results.

How to use

Use this calculator to see how your savings grow over time with compound interest. Start by entering your 'Initial Investment' (the amount you have right now). Next, input your 'Monthly Contribution'—the amount you plan to add each month.

Enter the expected 'Annual Interest Rate' (e.g., 6.5 for 6.5%) and the 'Time Period' in years. The calculator will determine your total future balance, separating how much you actually deposited from the interest you earned.

This is ideal for projecting retirement savings or long-term investment growth. Understanding your compounding schedule can help you better prepare for your financial goals, as more frequent compounding yields slightly higher returns over time.

How it's calculated

Total Amount

principal * pow(1 + annual_rate / 100 / compound_frequency, compound_frequency * years)

Total value of your investment after the period

Interest Earned

total_amount - principal

Total interest accumulated over the period

Effective Annual Rate

(pow(1 + annual_rate / 100 / compound_frequency, compound_frequency) - 1) * 100

The actual annual return accounting for compounding

Examples

10M VND at 8% monthly for 5 years

  • Investment Period (Years):5
  • Initial Investment:10,000,000
  • Annual Interest Rate (%):8
  • Compounding Frequency:12

Result

  • future_value:3,438,784,000
  • total_interest:2,138,784,000
  • total_principal:1,300,000,000

With a 100M VND starting amount and 10M VND added monthly at a 7% return over 10 years, you accumulate over 3.4 billion VND. More than 2.1 billion VND of this is purely from interest, showing the power of compounding.

50M VND at 6% yearly for 10 years

  • Investment Period (Years):10
  • Initial Investment:50,000,000
  • Annual Interest Rate (%):6
  • Compounding Frequency:1

Result

  • Total Amount:89,542,380
  • Effective Annual Rate:6.0%
  • Interest Earned:39,542,380

50 million₫ invested at 6% compounded annually grows to 89.5 million₫ after 10 years — nearly doubling. This illustrates the Rule of 72: at 6%, money doubles roughly every 12 years. Starting early is the most powerful lever for long-term wealth.

Industry Benchmarks

Metric Typical Range
Historically, long term broad market equity investments yield around 7.5% to 10% annually. 7.5 % (Average VN stock market return)

Data source: Historical VN-Index Data

Frequently Asked Questions

What is compound interest?

Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, which is only calculated on the principal amount, compound interest causes your investment to grow exponentially over time. This 'interest on interest' effect accelerates your wealth building.

How does compounding frequency affect returns?

The more frequently interest is compounded, the higher your effective annual return will be. For example, daily compounding yields slightly more money than monthly compounding, which in turn yields more than yearly compounding at the same nominal interest rate. This makes the compounding frequency a crucial factor in long-term investments.

What is the effective annual rate (EAR)?

The EAR is the actual annual return after accounting for compounding within the year. It is always equal to or higher than the nominal annual rate, and is useful for comparing investments with different compounding frequencies.

How often is the interest compounded in this tool?

This calculator assumes monthly compounding by default, which is standard for most personal savings accounts, certificates of deposit, and monthly investment plans. However, you can change the compounding frequency to yearly or daily to better match your specific financial products and see how the growth curve changes.
CalcVault Editorial Team

CalcVault Editorial Team

Verified Content Team

The CalcVault Editorial Team is a group of finance, health, and mathematics specialists dedicated to producing accurate, bilingual calculator content for Vietnamese and global small business owners. Every formula on CalcVault undergoes rigorous source verification against authoritative bodies including the IRS, CFPB, CDC, WHO, and NIST before publication. Our process includes independent peer review, structured fact-checking, and scheduled content audits to ensure every calculator remains up-to-date with the latest regulatory and scientific standards. We are committed to editorial independence from our advertising partners.

Areas of Expertise

Personal FinanceVietnam Tax & PayrollHealth Metrics & BMIApplied MathematicsBusiness LendingSMB Financial Planning
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