The open-source packages, references, and documentation sites that power the Empire Hub calculators.
Every link on this page is a reviewed, dofollow link to a resource we own and maintain.
Pure, dependency-free Go math that computes precious-metal melt value from karat, weight, and a live spot price. The engine behind GoldGramPrice.
Debt service coverage ratio (DSCR) for rental-property loans: NOI ÷ annual debt service. The engine behind DSCRRadar.
2025 US federal income tax (progressive brackets plus standard deduction) and FICA take-home math. The engine behind StateWage.
Reservoir and lake elevation math: percent-of-pool, storage conversions, and datum conversions. The engine behind LakeLevelNow.
2025/26 UK income tax bands for England, Wales and Northern Ireland, the personal-allowance taper, and National Insurance. The engine behind UKMoneyCalc.
Loan amortization: monthly payment, per-period breakdown, total interest, and remaining balance. The engine behind AssetLoanCalculator.
Baker's percentages, dough hydration, and recipe scaling by flour weight. The engine behind IngredientCalculator.
Estimates the OBBBA above-the-line deduction for qualified overtime compensation, including the MAGI phase-out. The engine behind NoOvertimeTax.
Estimates OBBBA individual tax breaks: the increased standard deduction and the overtime and tips above-the-line deductions. The engine behind TaxBreakCalc.
Equity valuation ratios: P/E, P/B, earnings yield, EV/EBIT and dividend yield. The engine behind DeepValueRadar.
Estimates a digital-SAT total scaled score (400 to 1600) from raw correct answers, using a transparent linear model. The engine behind ExamScoreCalc.
MkDocs Material documentation for the gold-melt-value package: melt value by karat, weight, and live spot price.
MkDocs Material documentation for the dscr-ratio package: DSCR for rental-property and investment real-estate loans.
Open repositories of the reference data behind these calculators (tax brackets, lake-level feeds, spot-price series, HS tariff tables). Zenodo DOI deposits for the long-running series are published from these repos as they stabilize.
Longer write-ups behind the calculators: how full-pool elevation differs from depth, why the personal-allowance taper creates a 60 percent marginal band, why DSCR moves faster on loan term than on rent, and which OBBBA provisions expire. Each post works from the published reference data rather than summarising it.