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Compound Interest: Calculator iconCompound Interest: Calculator
Compound Interest: Calculator iconIn reviewPreparing for App Store release · iPhone and iPad

Finance calculator

Compound Interest: Calculator — see how your money could grow

Compound Interest: Calculator is a financial calculation and planning app from Three Two One Global that models compound growth from assumptions you enter, with charts, year-by-year breakdowns and scenario comparison.

Explore projected balances, contributions and estimated interest — without connecting a bank account or receiving financial advice.

An informational calculator only — not financial advice, and currency display does not convert exchange rates.

Support
  • Compound Interest: Calculator — Enter starting amount, interest rate, duration, contributions and compounding frequency.
  • Compound Interest: Calculator — Review projected balance, contribution totals and estimated interest with an interactive growth chart.
  • Compound Interest: Calculator — Inspect each year with starting balance, contributions, interest earned and ending balance.
  • Compound Interest: Calculator — Compare two planning scenarios side by side for projected balance, contributions and interest.

Overview

A calculator for compound growth scenarios

Instead of building projections in a spreadsheet, Compound Interest: Calculator helps you model an initial amount, interest rate, duration and regular contributions, then review clear charts and year-by-year estimates based on your assumptions.

Compound Interest: Calculator is a financial calculation and planning tool from Three Two One Global. Enter your assumptions to explore projected balances, contributions, estimated interest, interactive charts and year-by-year breakdowns — without connecting a bank account.

Details

What you can do

Project balances from your assumptions

Enter starting amount, interest rate, time horizon, contribution settings and compounding frequency to explore an estimated future balance. Results are estimates — not guaranteed investment returns.

Compare scenarios and save plans

Save calculations and compare scenarios so you can see how different contribution levels, rates or time horizons change the projected outcome.

Important: a calculator, not an investment service

The App does not connect to banks, move money, execute trades or provide regulated financial advice. Currency selection changes display symbols only and does not convert foreign-exchange rates.

Product

From inputs to year-by-year projections

Enter assumptions, review growth charts, inspect yearly breakdowns and compare planning scenarios.

  • Compound Interest: Calculator — Enter starting amount, interest rate, duration, contributions and compounding frequency.
  • Compound Interest: Calculator — Review projected balance, contribution totals and estimated interest with an interactive growth chart.
  • Compound Interest: Calculator — Inspect each year with starting balance, contributions, interest earned and ending balance.
  • Compound Interest: Calculator — Compare two planning scenarios side by side for projected balance, contributions and interest.

  1. 01 · Calculator inputs

    Enter starting amount, interest rate, duration, contributions and compounding frequency.

  2. 02 · Projected balance

    Review projected balance, contribution totals and estimated interest with an interactive growth chart.

  3. 03 · Year-by-year breakdown

    Inspect each year with starting balance, contributions, interest earned and ending balance.

  4. 04 · Compare scenarios

    Compare two planning scenarios side by side for projected balance, contributions and interest.

Features

Clear compound-growth modelling

Compound growth calculations

Model an initial investment with an interest rate, duration and compounding frequency to explore estimated future balances.

Regular contributions

Add recurring contributions and contribution frequencies so your projection reflects ongoing saving habits.

Visual growth charts

See growth over time with interactive charts that break out totals, contributions and interest.

Year-by-year breakdown

Review each year of a projection with starting balance, contributions, interest earned and ending balance.

Save and compare scenarios

Save calculation plans and compare scenarios so you can explore how different assumptions change outcomes.

Advanced assumptions

Adjust advanced options such as inflation assumptions and contribution-increase assumptions where available.

Multiple display currencies

Choose a currency symbol for display. Currency selection does not perform foreign-exchange conversion.

Process

How Compound Interest: Calculator works

  1. Step 01

    Enter your assumptions

    Set starting amount, interest rate, duration, contributions, compounding frequency and any advanced options you want to model.

  2. Step 02

    Review the projection

    See projected balance, total contributions, estimated interest and interactive charts based on the values you entered.

  3. Step 03

    Save or compare scenarios

    Keep a plan for later or compare scenarios side by side to understand how different assumptions change the estimate.

Audience

Who Compound Interest: Calculator is for

  • People who want a clear compound-interest projection without a spreadsheet

  • Savers exploring how regular contributions may affect long-term estimates

  • Anyone comparing planning scenarios before speaking with a qualified professional

What this App is not

Compound Interest: Calculator is not a bank, brokerage, investment platform or source of regulated financial advice. It does not guarantee future returns, and displayed currency is for modelling display only.

Privacy

Built for calculation, not bank access

Compound Interest: Calculator is designed as a modelling tool. It does not require a bank connection to run calculations.

Read the full Privacy Policy for exactly what may be processed and why.

View the full privacy policy
  • Calculator inputs are assumptions you enter — not live bank balances or account credentials.
  • The App does not connect to bank accounts, move money or execute trades.
  • Subscriptions and entitlements are managed through Apple and RevenueCat; we do not receive your full payment card details.
  • We use PostHog for product analytics to understand usage and improve the App, as described in the Privacy Policy.

FAQ

Common questions

What is Compound Interest: Calculator?

It is a financial calculation and planning app from Three Two One Global that models compound growth using assumptions you enter, with charts and year-by-year projections.

Does the App give investment advice?

No. The App is an informational calculator only. It does not provide financial, investment, tax, legal or accounting advice.

Do I need to connect a bank account?

No. Calculator inputs are assumptions you enter. The App does not require a bank connection to run calculations.

Are projected balances guaranteed?

No. Results are estimates based on your inputs. Actual returns, fees, taxes, inflation and other factors can differ materially.

Does currency selection convert money between currencies?

No. Choosing a currency changes the displayed symbol for modelling. It does not perform foreign-exchange conversion.

Is the App available to download yet?

Compound Interest: Calculator is preparing for App Store submission. Official App Store links will appear here when available.

Preparing for App Store release

Compound Interest: Calculator is preparing for submission. Check back soon for download details.

In reviewGet support

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