Focused formula, content, and source review.
Loading page
Every calculator has a visible status.
Verified does not mean infallible. It means the formula has focused review coverage, a transparent method, and a defined scope. Limited and experimental tools are labeled so their boundaries stay clear.
Automated tests and documented calculation method.
Useful estimate with important domain limitations.
Narrow mathematical or educational scope under active refinement.
Deterministic calculations
Calculator answers come from code and visible inputs—not generated guesses.
Correction path
Disputed results can be reported with reproducible inputs and official evidence.
Release gates
Tests, type safety, production compilation, registry coverage, and integrity checks run before release.
Registry
218 published calculators
| Calculator | Area | Status | Reviewed | Sources |
|---|---|---|---|---|
| Car Running Cost | Automotive | Maintained | September 12, 2026 | 2 |
| Emergency Fund | Finance | Maintained | September 12, 2026 | 1 |
| Dealer Fees | Automotive | Maintained | September 12, 2026 | 2 |
| Mortgage Points | Finance | Maintained | September 12, 2026 | 1 |
| Loan Payoff | Finance | Maintained | September 12, 2026 | 1 |
| Auto Refinance | Automotive | Verified | September 12, 2026 | 2 |
| Car Affordability | Automotive | Verified | October 14, 2026 | 1 |
| Mortgage Affordability | Finance | Verified | September 12, 2026 | 1 |
| Savings Goal | Finance | Maintained | September 12, 2026 | 1 |
| Percentage Change | Math | Maintained | September 12, 2026 | 1 |
| Discount | Math | Maintained | September 12, 2026 | 1 |
| Sales Tax | Math | Maintained | September 12, 2026 | 1 |
| Tip & Bill Split | Math | Maintained | September 12, 2026 | 1 |
| Auto Lease | Automotive | Verified | September 12, 2026 | 2 |
| Lease vs Buy | Automotive | Verified | September 12, 2026 | 2 |
| Refinance Break-even | Automotive | Maintained | September 12, 2026 | 2 |
| Mortgage Refinance | Finance | Verified | September 12, 2026 | 1 |
| Rent vs Buy | Finance | Maintained | September 12, 2026 | 1 |
| Debt Consolidation | Finance | Verified | October 14, 2026 | 1 |
| Credit Card Payoff | Finance | Verified | September 12, 2026 | 1 |
| Investment Return | Finance | Verified | September 12, 2026 | 1 |
| Profit Margin | Finance | Verified | September 12, 2026 | 1 |
| Markup & Price | Finance | Maintained | September 12, 2026 | 1 |
| Business Break-even | Finance | Verified | September 12, 2026 | 1 |
| Snowball vs. Avalanche | Finance | Maintained | September 12, 2026 | 1 |
| Lease Buyout | Automotive | Maintained | September 12, 2026 | 2 |
| Mortgage Extra Payments | Finance | Maintained | September 12, 2026 | 1 |
| Mortgage Closing Costs | Finance | Verified | September 12, 2026 | 1 |
| PMI Removal | Finance | Verified | September 12, 2026 | 1 |
| Biweekly Mortgage | Finance | Verified | September 12, 2026 | 1 |
| Home Sale Proceeds | Finance | Verified | September 12, 2026 | 1 |
| Paycheck | Finance | Limited scope | September 12, 2026 | 3 |
| Cash vs. Finance | Automotive | Maintained | September 12, 2026 | 2 |
| Negative Equity | Automotive | Verified | September 12, 2026 | 2 |
| Vehicle Depreciation | Automotive | Verified | September 12, 2026 | 2 |
| Dealer Profit | Automotive | Maintained | September 12, 2026 | 2 |
| Vehicle Sales Tax | Automotive | Limited scope | September 12, 2026 | 1 |
| Salary vs. Hourly | Finance | Verified | September 12, 2026 | 1 |
| Freelance Rate | Finance | Maintained | September 12, 2026 | 1 |
| Fixed vs. ARM | Finance | Maintained | September 12, 2026 | 1 |
| Linear Equation | Math Lab | Maintained | September 12, 2026 | 1 |
| Quadratic Equation | Math Lab | Maintained | September 12, 2026 | 1 |
| Function Graph | Math Lab | Maintained | September 12, 2026 | 1 |
| Derivative | Math Lab | Maintained | September 12, 2026 | 1 |
| Definite Integral | Math Lab | Maintained | September 12, 2026 | 1 |
| Equation System | Math Lab | Maintained | September 12, 2026 | 1 |
| BMI | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Calorie Needs | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Weight Change Timeline | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Protein Intake | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Heart Rate Zone | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Running Pace | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Hourly to Salary | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Overtime Pay | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Pay Raise | Income & Work | Verified | 2026-09-12 | Method + tests |
| Sales Commission | Income & Work | Maintained | 2026-09-12 | Method + tests |
| PTO Value | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Cost of Living Comparison | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Rental Property Cash Flow | Real Estate | Verified | 2026-09-12 | Method + tests |
| Cap Rate | Real Estate | Verified | 2026-09-12 | Method + tests |
| Cash-on-Cash Return | Real Estate | Maintained | 2026-09-12 | Method + tests |
| HELOC Payment | Real Estate | Maintained | 2026-09-12 | Method + tests |
| Home Appreciation | Real Estate | Maintained | 2026-09-12 | Method + tests |
| DSCR | Real Estate | Maintained | 2026-09-12 | Method + tests |
| Employee True-Cost | Business | Maintained | September 12, 2026 | 1 |
| Inventory Turnover | Business | Maintained | September 12, 2026 | 1 |
| Reorder Point | Business | Maintained | September 12, 2026 | 1 |
| Customer Acquisition Cost | Business | Maintained | September 12, 2026 | 1 |
| Customer Lifetime Value | Business | Maintained | September 12, 2026 | 1 |
| Monthly Recurring Revenue | Business | Maintained | September 12, 2026 | 1 |
| Fuel Cost | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| EV Charging Cost | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Commute Cost | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Electricity Cost | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Subscription Cost | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Recipe Scaling | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Fraction | Math Lab | Maintained | September 12, 2026 | 1 |
| Ratio & Proportion Solver | Math Lab | Maintained | September 12, 2026 | 1 |
| Exponent | Math Lab | Maintained | September 12, 2026 | 1 |
| Right Triangle | Math Lab | Maintained | September 12, 2026 | 1 |
| Standard Deviation | Math Lab | Maintained | September 12, 2026 | 1 |
| Probability | Math Lab | Maintained | September 12, 2026 | 1 |
| Combinations | Math Lab | Maintained | September 12, 2026 | 1 |
| 401(k) | Finance | Verified | September 12, 2026 | 1 |
| Retirement | Finance | Verified | September 12, 2026 | 1 |
| Roth vs Traditional IRA | Finance | Maintained | September 12, 2026 | 1 |
| Social Security Break-Even | Finance | Maintained | September 12, 2026 | 1 |
| Required Minimum Distribution | Finance | Maintained | September 12, 2026 | 1 |
| Student Loan | Finance | Maintained | September 12, 2026 | 1 |
| Student Loan Refinance | Finance | Maintained | September 12, 2026 | 1 |
| Credit Card Balance Transfer | Finance | Maintained | September 12, 2026 | 1 |
| Credit Utilization | Finance | Maintained | September 12, 2026 | 1 |
| Net Worth | Finance | Maintained | September 12, 2026 | 1 |
| Monthly Budget | Finance | Maintained | September 12, 2026 | 1 |
| APR vs Interest Rate | Finance | Maintained | September 12, 2026 | 1 |
| CD | Finance | Maintained | September 12, 2026 | 1 |
| Bond Yield | Finance | Maintained | September 12, 2026 | 1 |
| Investment Fee Impact | Finance | Verified | October 10, 2026 | 1 |
| Mortgage Recast | Real Estate | Verified | October 10, 2026 | 1 |
| Home Equity Loan | Real Estate | Verified | October 10, 2026 | 1 |
| Construction Loan | Real Estate | Maintained | 2026-09-12 | Method + tests |
| Land Loan | Real Estate | Verified | October 10, 2026 | 1 |
| Property Tax | Real Estate | Limited scope | 2026-09-12 | Method + tests |
| House-Flipping Profit | Real Estate | Maintained | 2026-09-12 | Method + tests |
| Short-Term Rental | Real Estate | Maintained | 2026-09-12 | Method + tests |
| BRRRR | Real Estate | Maintained | 2026-09-12 | Method + tests |
| 1031 Exchange | Real Estate | Maintained | 2026-09-12 | Method + tests |
| Commercial Mortgage | Real Estate | Verified | October 10, 2026 | 2 |
| Loan-to-Value | Real Estate | Maintained | 2026-09-12 | Method + tests |
| Home Improvement ROI | Real Estate | Verified | 2026-09-12 | Method + tests |
| EV vs Gas Total Cost | Automotive | Maintained | September 12, 2026 | 2 |
| Extended Warranty Break-Even | Automotive | Maintained | September 12, 2026 | 2 |
| Lease Mileage Overage | Automotive | Maintained | September 12, 2026 | 2 |
| Early Lease Termination | Automotive | Maintained | September 12, 2026 | 2 |
| Auto Loan Rate Buydown | Automotive | Maintained | September 12, 2026 | 2 |
| Dealer Holdback | Automotive | Maintained | September 12, 2026 | 2 |
| Vehicle Registration Cost Estimator | Automotive | Maintained | September 12, 2026 | 2 |
| Fleet Cost | Automotive | Maintained | September 12, 2026 | 2 |
| Car Insurance Deductible | Automotive | Maintained | September 12, 2026 | 2 |
| Repair vs Replace Car | Automotive | Maintained | September 12, 2026 | 2 |
| Business Cash Runway | Business | Maintained | September 12, 2026 | 1 |
| Burn Rate | Business | Maintained | September 12, 2026 | 1 |
| Contribution Margin | Business | Maintained | September 12, 2026 | 1 |
| Operating Margin | Business | Maintained | September 12, 2026 | 1 |
| EBITDA | Business | Maintained | September 12, 2026 | 1 |
| Cash Conversion Cycle | Business | Maintained | September 12, 2026 | 1 |
| Churn Impact | Business | Maintained | September 12, 2026 | 1 |
| SaaS LTV to CAC | Business | Maintained | September 12, 2026 | 1 |
| Product Pricing | Business | Maintained | September 12, 2026 | 1 |
| Payroll Cost | Business | Maintained | September 12, 2026 | 1 |
| Equipment Lease vs Buy | Business | Maintained | September 12, 2026 | 1 |
| Invoice Late Fee | Business | Maintained | September 12, 2026 | 1 |
| Reverse Sales Tax | Business | Maintained | September 12, 2026 | 1 |
| Contractor vs Employee | Income & Work | Verified | 2026-09-12 | Method + tests |
| Job Offer Comparison | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Bonus Tax | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Severance | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Employee Benefits Value | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Take-Home Pay Comparison | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Shift Differential | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Double-Time Pay | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Monthly Income | Income & Work | Verified | October 11, 2026 | 3 |
| Multiple Income | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Irregular Income | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Gig Work Earnings | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Income Goal | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Tiered Commission | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Tips & Shift Income | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Freelance Capacity | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Income Interruption | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Matrix | Math | Maintained | September 12, 2026 | 1 |
| Polynomial Roots | Math | Maintained | September 12, 2026 | 1 |
| Limit | Math | Experimental | September 12, 2026 | 1 |
| Indefinite Integral | Math | Experimental | September 12, 2026 | 1 |
| Trigonometry | Math | Maintained | September 12, 2026 | 1 |
| Complex Number | Math | Maintained | September 12, 2026 | 1 |
| Logarithm | Math | Maintained | September 12, 2026 | 1 |
| Scientific Notation | Math | Maintained | September 12, 2026 | 1 |
| Normal Distribution | Math | Experimental | September 12, 2026 | 1 |
| Confidence Interval | Math | Experimental | September 12, 2026 | 1 |
| Linear Regression | Math | Experimental | September 12, 2026 | 1 |
| Geometry Workspace | Math | Maintained | September 12, 2026 | 1 |
| Body Fat | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Lean Body Mass | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Macro | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Water Intake | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Pregnancy Due Date | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Sleep | Health & Fitness | Limited scope | 2026-09-12 | Method + tests |
| Unit Price | Everyday Life | Verified | October 14, 2026 | 1 |
| Inflation | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Working Days | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Moving Cost | Everyday Life | Verified | October 10, 2026 | 1 |
| Travel Budget | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Appliance Operating Cost | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Mortgage Assumption | Real Estate | Maintained | 2026-09-12 | Method + tests |
| Seller Financing | Real Estate | Maintained | 2026-09-12 | Method + tests |
| Property Tax Reassessment | Real Estate | Maintained | 2026-09-12 | Method + tests |
| Solar Break-Even | Real Estate | Maintained | 2026-09-12 | Method + tests |
| Negative Equity Recovery | Automotive | Maintained | September 12, 2026 | 2 |
| Dealer vs Bank Financing | Automotive | Verified | October 10, 2026 | 1 |
| Roth Conversion | Finance | Maintained | September 12, 2026 | 1 |
| Ecommerce Profitability | Business | Maintained | September 12, 2026 | 1 |
| Student Loan IDR Comparison | Finance | Maintained | September 12, 2026 | 1 |
| Bridge Loan | Finance | Maintained | September 12, 2026 | 1 |
| Retirement Withdrawal | Finance | Maintained | September 12, 2026 | 1 |
| Pension Lump Sum vs. Monthly | Finance | Maintained | September 12, 2026 | 1 |
| Retirement Income Gap | Finance | Maintained | September 12, 2026 | 1 |
| Childcare Affordability | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Parental Leave | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Family Budget | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| College Savings | Finance | Maintained | September 12, 2026 | 1 |
| Tuition Growth | Finance | Maintained | September 12, 2026 | 1 |
| Life Insurance Needs | Finance | Maintained | September 12, 2026 | 1 |
| Disability Income Gap | Finance | Maintained | September 12, 2026 | 1 |
| Small Business Tax Reserve | Business | Maintained | September 12, 2026 | 1 |
| Owner Compensation | Business | Maintained | September 12, 2026 | 1 |
| Marketplace Fee | Business | Maintained | September 12, 2026 | 1 |
| Ecommerce Shipping | Business | Maintained | September 12, 2026 | 1 |
| Advertising Break-Even | Business | Maintained | September 12, 2026 | 1 |
| Contractor Project Pricing | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Professional Services Utilization | Business | Maintained | September 12, 2026 | 1 |
| Exponential Growth & Decay | Math | Maintained | September 12, 2026 | 1 |
| Arithmetic & Geometric Sequence | Math | Maintained | September 12, 2026 | 1 |
| Cash-Out Refinance | Finance | Maintained | September 12, 2026 | 1 |
| Home Equity | Finance | Maintained | September 12, 2026 | 1 |
| Auto Loan Early Payoff | Finance | Maintained | September 12, 2026 | 1 |
| Car Lease Mileage | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Investment Fee Comparison | Finance | Maintained | September 12, 2026 | 1 |
| Salary After-Tax Comparison | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Freelance vs. Employee | Income & Work | Maintained | 2026-09-12 | Method + tests |
| Price per Unit Comparison | Everyday Life | Maintained | 2026-09-12 | Method + tests |
| Personal Loan | Finance | Verified | September 12, 2026 | 1 |
| Debt-to-Income | Finance | Verified | October 14, 2026 | 1 |
| Car Payment | Automotive | Verified | September 12, 2026 | 2 |
| Auto Loan | Automotive | Verified | September 12, 2026 | 2 |
| Mortgage | Finance | Verified | September 12, 2026 | 1 |
| Percentage | Math | Maintained | September 12, 2026 | 1 |
| Compound Interest | Finance | Verified | September 12, 2026 | 1 |