Savings Interest Calculator

📖 Tool Introduction

Savings Interest Calculator is a free online tool that helps depositors estimate the maturity value of a bank fixed deposit, a government bond or a wealth-management product in seconds. When a bank relationship manager quotes an annual interest rate, most people can only guess how much interest their money will actually earn over a three-year term, and when they read the difference between simple interest and compound interest in a product brochure, few of them have the patience to work through the numbers year by year. This tool turns principal, annual rate and term into a clean form, and lets you pick how often interest is compounded: yearly, half-yearly, quarterly or monthly. Once you click Calculate, two cards at the top show the maturity amount under simple interest and under compound interest side by side, with a small note revealing exactly how much extra the compounding schedule earns you; below them, a year-by-year table lists the simple balance, the compound balance and the interest gap for the first thirty years, so the snowball effect of time and rate becomes a visible staircase of numbers rather than an abstract concept. Everything runs locally in your browser with no network request and no account, the interface is available in Simplified Chinese, Traditional Chinese and English, and the layout adapts smoothly to narrow phone screens, which makes it a practical companion for first-time savers, salaried workers and older family members who want to see clearly how their money grows inside a bank product. Because the whole process takes only a few seconds, it is also handy when you are comparing two deposit offers on the spot and need to decide which one actually leaves more in your pocket at maturity, without pulling out a spreadsheet or asking the staff to repeat the explanation a second time.

✨ Key Features

• Simple interest follows the textbook formula principal × rate × term, matching bank conventions
• Compound interest supports yearly, half-yearly, quarterly and monthly compounding frequencies
• Two result cards placed side by side, so the simple-versus-compound gap is visible at a glance
• A year-by-year table covering up to the first thirty years of balances and the interest gap
• An explicit "compound earns extra" note that quantifies the snowball advantage
• One-click copy and download, so the comparison can be shared or archived as a text file

📝 How to Use

1. Type the amount you plan to deposit into the principal field
2. Enter the annual rate, for example 3.5 means 3.5 percent per year
3. Enter the term in years and choose the compounding frequency
4. Click Calculate and read the two cards above together with the yearly table below
5. Click Copy or Download to keep the result, or Clear to run another scenario

⚠️ Notes

• Valid input: principal and rate must not be negative, and the term must be greater than zero years
• Rate basis: enter the annual rate as a percentage; convert a monthly rate by multiplying by twelve first
• Compounding choice: ordinary bank fixed deposits usually use simple interest, while wealth products often compound
• Local only: every calculation runs inside the browser with no network request at all
• For reference: actual interest follows the bank's posted rate and rules, so treat this tool as an estimate