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
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
What's New in CompoundFX 1.2
More accurate Goal Mode
• Tax-aware solving: Goal Mode now fully accounts for annual tax treatment when solving for rate, duration, principal, or deposit. Your solved values land exactly on target.
Settings that respond instantly
• Live tax treatment: Switching between Annual and Deferred tax treatment now updates your current scenario immediately. There's no need to start a new scenario to see the change.
Refined calculations
• Smarter tax modeling: Tax is no longer applied against negative returns in high-fee, low-return scenarios, keeping after-tax projections conservative and correct.
• Consistent formatting: Currency displays are now locked to a consistent format on every device, regardless of region settings.
Under the hood
• Snappier response: Rate of Return now recalculates dramatically faster while you adjust sliders.
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.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Origin Software, Inc.
- Size
- 4.5 MB
- Category
- Finance
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- CompoundFX Pro $4.99
- Copyright
- © 2026 Origin Software, Inc.

