About Decision Tools
Decision Tools exists to make everyday decisions clearer. We build objective, non-prescriptive calculators and frameworks designed to clarify costs, time, and practical trade-offs.
We do NOT tell you what you should choose.
Every major decision in life—from buying a house or accepting a new job offer to leasing a car or repairing an appliance—involves personal circumstances, risk tolerance, and unique priorities that no algorithm can know.
Our models calculate the mathematical outcomes and expose the underlying trade-offs so you can make your own informed choice with confidence.
Our Analytical Pillars
Zero Commercial Bias
We do not accept sponsored product placements, affiliate commissions for recommending specific lenders or vehicles, or payments to tilt calculation results. Our algorithms are independent and open.
Formula Transparency
Every amortization schedule, depreciation curve, and tax adjustment is documented in plain English. You can inspect the exact assumptions and override every parameter.
Opportunity Cost Accounting
Real-world decisions do not exist in a vacuum. We account for what capital or time could accomplish if deployed elsewhere, including investment compounding and unpaid commute hours.
Language Discipline
You will never see words like "Winner," "Best Choice," or "Recommended Option" in our tools. We report numerical differences and sensitivity ranges neutrally.
Methodology & Modeling Standards
Deterministic Computation
All mathematical calculations run client-side in deterministic TypeScript. They do not rely on opaque generative AI predictions or probabilistic guesses. When you input an interest rate and term, the amortization formula matches standard banking actuarial tables.
Standard Amortization Formulas
For mortgage, debt, and loan calculations, we apply standard compound interest equations:
M = P * [r(1+r)^n] / [(1+r)^n - 1]Where M is the monthly payment, P is principal, r is monthly interest rate, and n is total months.
Empirical Benchmarks
Default values are grounded in reliable public sector and economic data:
- IRS Standard Mileage Rate (Contextual Benchmark): The IRS standard business mileage rate is referenced solely as an illustrative public benchmark for comprehensive vehicle operating expenses (fuel, routine maintenance, tires, insurance, and asset depreciation wear). It does not represent tax advice or personal commuting deduction guidance, as ordinary commuting is non-deductible under federal tax rules.
- Federal Highway Administration (FHWA): Average annual household vehicle travel benchmark of approximately 13,500–14,000 miles per year (derived from FHWA Highway Statistics series data).
- U.S. Energy Information Administration (EIA): Baseline residential electricity tariffs ($/kWh) and retail motor gasoline prices ($/gallon) reference EIA monthly and annual state-level utility averages.
Data Privacy & Security
Your Numbers Stay in Your Browser
When you enter your salary, mortgage balances, debt figures, or personal vehicle numbers into Decision Tools, that data is processed entirely in your browser memory. We do not store your inputs on remote servers, we do not require account registration, and we do not sell financial profiling data.