--- title: "Compound Interest Calculator | Numequo" description: "See how savings may grow with monthly compounding. Get a clear result with the formula, examples and useful explanations." canonical: "https://www.numequo.com/finance/savings-investing/compound-interest-calculator/" locale: "en" --- [Numequo](https://www.numequo.com/) › [Finance](https://www.numequo.com/finance/) › [Savings and investing](https://www.numequo.com/finance/savings-investing/) # Compound Interest Calculator Project an initial amount plus regular monthly contributions. ## Input data - **Starting amount** - type: number; default: 10000; min: 0; max: 1000000000; step: 100 - **Monthly contribution** - type: number; default: 200; min: 0; max: 10000000; step: 10 - **Annual return (%)** - type: number; default: 5; min: -99; max: 100; step: 0.01 - **Duration (years)** - type: number; default: 10; min: 1; max: 100; step: 1 - **Currency** - type: choice; default: EUR; options: Euro (€), US dollar ($), British pound (£) - **Account for inflation** - type: choice; default: no; options: Enabled, Disabled - **Average annual inflation (%)** - type: number; default: 1.6; min: -99; max: 100; step: 0.01; Default: France's annualized average from 2005 to 2025 (Insee CPI). ## How it works Future value combines the compounded principal and end-of-month contributions. When inflation is enabled, it is divided by (1 + inflation rate) raised to the projection duration. ## Quick examples - **€10k + €200/month** - Starting amount: 10000, Monthly contribution: 200, Annual return (%): 5, Duration (years): 10, Currency: EUR - **$1k + $100/month** - Starting amount: 1000, Monthly contribution: 100, Annual return (%): 7, Duration (years): 20, Currency: USD - **No monthly contribution** - Starting amount: 25000, Monthly contribution: 0, Annual return (%): 4, Duration (years): 15, Currency: EUR ## Understanding your result The nominal balance is the amount shown in the future. The inflation-adjusted result estimates what it could buy in today's money. Inflation is an assumption and may differ from actual future price changes. Last verified: 29 September 2026 (2026-09-29) ## Sources - Insee: Annual CPI series used for the 2005–2025 average ## Frequently asked questions ### What is compound interest? It is interest earned on both the original amount and earlier interest. ### When are contributions added? This calculator assumes contributions are made at the end of each month. ### Does this include taxes or fees? Taxes and fees are not included. Inflation can be enabled separately to express the result in today's money. ### Is the return guaranteed? No. It is a mathematical projection, not an investment forecast. ## Related calculators - [Savings Goal Calculator](https://www.numequo.com/finance/savings-investing/savings-goal-calculator/) - Calculate when you could reach a savings target or how much to save each month. - [Investment Fee Calculator](https://www.numequo.com/finance/savings-investing/investment-fee-calculator/) - Compare how two annual fee rates affect a portfolio’s long-term value. - [Rent or Buy Calculator](https://www.numequo.com/finance/real-estate/rent-or-buy-calculator/) - Compare projected homeowner equity with the renter’s invested capital over time. - [Loan Calculator](https://www.numequo.com/finance/loans/loan-calculator/) - Estimate monthly payments and total loan cost. - [VAT Calculator](https://www.numequo.com/finance/taxes-pricing/vat-calculator/) - Add VAT to a net price or extract it from a gross price. - [Debt-to-Income Ratio Calculator](https://www.numequo.com/finance/loans/debt-to-income-ratio-calculator/) - Calculate your household debt-to-income ratio, total monthly debt payments and remaining income after debt. ## Structured data ```json { "@context": "https://schema.org", "@graph": [ { "@type": "WebPage", "@id": "https://www.numequo.com/finance/savings-investing/compound-interest-calculator/#page", "name": "Compound Interest Calculator | Numequo", "description": "See how savings may grow with monthly compounding. 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Inflation can be enabled separately to express the result in today's money." } }, { "@type": "Question", "name": "Is the return guaranteed?", "acceptedAnswer": { "@type": "Answer", "text": "No. It is a mathematical projection, not an investment forecast." } } ] } ] } ```