CompoundFX: Compound Interest

Investment Finance Calculator

Only for iPhone

Free · In‑App Purchases

iPhone

Stop using basic calculators that ignore reality. CompoundFX models true investment growth by letting you easily factor in expense ratios, tax drag, and inflation. CompoundFX is the compound interest calculator that shows you what it takes, not just what you'll have. Model investment growth, plan for retirement, and pressure-test your FIRE goals with precision. Set a goal, $1M by age 60, a down payment, or a college fund, and CompoundFX solves for the missing piece. The rate you’ll need. The years it will take. The deposit you have to make. No more guessing. No more trial and error. GOAL MODE Pick your goal. Choose what to solve for. CompoundFX does the financial math. - Solve for Rate of Return - Solve for Time Horizon - Solve for Starting Principal - Solve for Monthly Contribution COMPARE SCENARIOS Should you save more or invest longer? Pay off debt or boost your 401(k)? Save scenarios and put them head-to-head. See the difference, the total dollar impact, and exactly when one strategy pulls ahead. A CALCULATOR THAT SHOWS ITS WORK - Real-time growth chart with milestone markers ($100K, $250K, $1M) - Year-by-year breakdown with full transparency - Inflation, Taxes, and Expense Ratios: See what you actually keep after fee drag - Daily, weekly, monthly, or annual contributions - Custom compounding intervals (Daily to Annually) - Sub-year precision for short-horizon plans DESIGNED FOR iPHONE & INDIE DEV Dark glass UI. Smooth haptics. Built natively in SwiftUI for iOS 17 and up. No accounts. No ads. No tracking. Your scenarios stay locally on your device. EXPORT AND SHARE Generate a polished two-page PDF report with an executive summary, growth chart, and full milestone breakdown. Or share a branded image to text or social media. FREE FEATURES - Full compound interest calculator - Real-time growth chart and year-by-year table - Inflation, tax, and expense adjustments - Custom contribution and compounding schedules - Branded image sharing PRO: $4.99 (ONE-TIME PURCHASE) - Goal Mode (Solve for any missing variable) - Save unlimited scenarios - Compare scenarios side-by-side - Export two-page PDF reports One purchase. Unlocked forever. Family Sharing fully supported. WHO IT'S FOR Whether you're starting your first Roth IRA, managing index funds, planning early retirement, modeling a college fund, or tracking a Bogleheads portfolio, CompoundFX gives you the answer in seconds. PRIVACY FIRST CompoundFX is fully offline. No data collection. No accounts required. No analytics. No third-party SDKs. Your personal finance data is stored safely on your device. DISCLAIMER CompoundFX is for educational and planning purposes. It does not provide investment, tax, or financial advice. Returns shown are projections based on the inputs you provide and do not guarantee actual investment performance. Questions or feedback? support@originsoftware.net

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What’s New in CompoundFX 1.3 Tax treatment where you use it • New Tax control: In Advanced mode, the Tax input now has its own Deferred and Annual control, which updates your current scenario. • Defaults stay defaults: The Tax Treatment setting now sets the default for new scenarios only. It no longer changes the scenario you’re working on. Better on iPhone SE • More room to work: On iPhone SE, Advanced mode hides the sliders so every input fits on screen. Tap any value to edit it with the keypad. More accurate results • Rate of Return: Rate of Return now shows the correct value for extreme scenarios, such as very high rates and fees over long periods. • Large balances: Values of a trillion or more now display with a T in Year-by-Year, milestones, and the chart. Smarter Compare (Pro) • Clearer insights: Compare now explains why one scenario comes out ahead. It names the inputs that make the biggest difference and the ones working against the winner. • Fairer Goal Mode comparisons: Rates are compared as effective annual rates, deposits as yearly totals, and durations in years, so scenarios with different compounding or deposit schedules compare correctly. A scenario that can reach the goal now always beats one that can’t, and results too close to call are shown as a tie. • Faster exit: Done now closes Compare and returns you straight to the calculator. Refinements • Haptics: Haptics now follow your Haptic Feedback setting throughout the app. • Snappier menus: Menu items now open faster. Thank you for your support and feedback! If you’re loving the app, please consider leaving a review.

The developer, Origin Software, Inc., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

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    Seller
    Origin Software, Inc.
    Size
    4.6 MB
    Category
    Finance
    Compatibility
    Requires iOS 17.0 or later.
    • iPhone
      Requires iOS 17.0 or later.
    Languages
    English
    Age Rating
    4+
    In-App Purchases
    Yes
    Copyright
    © 2026 Origin Software, Inc.