Our Mission
Simple Finance Calculators exists to unlock financial knowledge for anyone making a housing decision. We read the same mortgage releases, rent indexes, and short term rental reports that professionals rely on and translate them into interactive tools that feel approachable, transparent, and bias free. Our mission is to keep every calculator honest with clear assumptions, cite the sources that inform our defaults, and update the math the moment new data is published so families, investors, and advisors can make smarter choices together.
Data Sources & Methodology
Every calculator calls out the data it uses. The core references refreshed monthly include:
- Bureau of Labor Statistics Shelter CPI and rent indexes
- Freddie Mac Primary Mortgage Market Survey for rate baselines
- HUD PMI thresholds, IRS Schedule E expense categories
- AirDNA and STR Insights for nightly rate and occupancy comps
Formulas are reviewed quarterly and whenever regulators update lending rules or tax guidance.
Update Cadence
Last updated: November 2025
Latest change: mobile scroll-to-results behavior and deferred schema improvements.
Last updated: November 2025
Latest change: unified Related Guides/Calculators and deferred JSON-LD for better performance.
Last updated: November 2025
Latest change: mobile scroll-to-results behavior and schema consolidation (SoftwareApplication + FAQ/HowTo).
Last updated: November 2025
Latest change: unified interlinking and deferred JSON-LD blocks.
Last updated: November 2025
Latest change: unified interlinking and deferred JSON-LD blocks.
Last updated: November 2025
Latest change: mobile scroll-to-results behavior and added Breadcrumb/FAQ/HowTo schema.
Last updated: November 2025
Latest change: mobile scroll-to-results behavior and methodology auto-expand improvements.
Last updated: November 2025
Latest change: initial launch with payment, available credit, and interest cost calculations.
Last updated: November 2025
Latest change: initial launch with employer match optimization, IRS contribution limits, paycheck impact analysis, and growth timeline visualization.
Last updated: November 2025
Latest change: initial launch with Lean/Regular/Fat/Coast/Barista FIRE scenario comparison and timeline visualization.
Last updated: December 2025
Latest change: initial launch with tax-deferred growth modeling, Rule of 72 visualization, and year-by-year breakdown.
Embed & API Integration
All our calculators can be embedded on your website or accessed via REST API. Whether you're a realtor adding value to listing pages, a mortgage broker capturing leads, a financial blogger enhancing content, or a developer building custom tools, we make it easy to integrate.
Perfect for real estate websites, mortgage broker sites, financial advisors, and bloggers. Add interactive calculators with one line of code.
✓ One-click embed codes
✓ Mobile-responsive widgets
✓ 100% free, no registration
✓ Clean attribution link included
Get Embed Codes →Build ChatGPT Custom GPTs, integrate with Claude, or power your own financial planning tools with our API.
✓ RESTful endpoints for all 10 calculators
✓ OpenAPI 3.0 specification
✓ CORS-enabled for cross-origin
✓ Free tier: 60 requests/minute
View API Documentation →Explore the Calculators
Jump directly into the tools that match your next decision.
Calculate how much house you can afford with income, debt, and DTI analysis.
Model your breakeven year with side by side rent and ownership costs.
Visualize principal, interest, and payoff timelines with escrow costs.
Stress test nightly rates, occupancy, and management fees before purchasing.
Calculate NOI, DSCR, cap rate, and cash flow for traditional lease investments.
Compare current vs new mortgage, see monthly savings, break-even timeline, and lifetime interest impact.
Calculate ARV, MAO, profit, ROI, and cash needed for house flips with hard money financing.
Calculate home equity line of credit payments, available credit, and total interest costs.
Calculate retirement account growth with employer match optimization, IRS contribution limits, and paycheck impact analysis.
Calculate your path to financial independence and early retirement with Lean, Regular, Fat, Coast, and Barista FIRE scenarios.
Visualize the power of compound growth with Rule of 72, year-by-year breakdown, and investment scenario comparisons.
Financial & Legal Disclaimers
Simple Finance Calculators is an educational resource. Our tools do not provide financial, investment, legal, accounting, or tax advice, and the outputs should never be the sole basis for a transaction. Actual loan terms, rent increases, occupancy rates, and expenses depend on your lender, jurisdiction, credit profile, and operational decisions. Always consult licensed mortgage professionals, attorneys, and tax advisors to validate assumptions, confirm regulatory obligations, and understand the legal implications of your strategy.
By using the calculators you acknowledge that you are responsible for compliance with all applicable laws, reporting requirements, insurance needs, and risk management decisions.