THE PROBLEM
Make complex compensation understandable.
Military take-home pay depends on more than basic pay. Allowances, special and incentive pays, retirement contributions, federal withholding, and deductions interact. CheckFire brings these inputs into a native iOS application for estimating monthly compensation and exploring saved paycheck scenarios.
Model the rules before presenting the result
The Paycheck model represents pay grade, years of service, entitlements, deductions, withholding inputs, and Traditional and Roth Thrift Savings Plan contributions. Pay components have explicit categories that determine their treatment in taxable wages, retirement contributions, and net pay.
Pay scenarioDecimal arithmetic
Financial modelSwiftUI + Charts
Pay breakdown
Financial calculations with explicit precision
Monetary calculations use Swift’s Decimal type, with shared rounding utilities for currency values. The model calculates contribution amounts and take-home pay from the configured compensation, taxes, and deductions. Making those operations explicit keeps the financial behavior inspectable.
Federal withholding tables are stored in tax-year-specific JSON and loaded through a dedicated repository. The withholding model applies filing status, multiple-job settings, dependents, other income, deductions, and additional withholding; it also estimates Social Security and Medicare. Separating table data from the algorithm makes annual data updates easier to maintain.
A persistent, reactive native interface
SwiftData stores paycheck scenarios locally, supporting creation, duplication, editing, and comparison. SwiftUI bindings and queries connect those models to reusable currency, pay-period, and contribution controls. Swift Charts presents the relationship between compensation, deductions, and estimated net pay.
From portfolio project toward App Store submission
CheckFire combines domain knowledge of military compensation with native interface design, persistent data modeling, and financial calculation logic. It remains under development, with App Store submission planned after further refinement and validation. It is not currently published on the App Store.
Next steps include validating calculation behavior against reference examples, strengthening automated coverage for withholding and rounding boundaries, and refining the experience for release.