MPG Basics and Calculation Guides
Core formulas, conversions, and practical guidance for understanding fuel economy clearly.
Quick Summary
This hub collects foundational MPG content: how to calculate fuel economy accurately, how to convert units, how to interpret city/highway ratings, and how to avoid common mistakes when comparing efficiency.
Start Here
If you are learning fuel economy fundamentals or want to sanity-check your current method, start with the guides below. They are organized to move from basic formulas to deeper interpretation and comparison topics.
2026 Mileage Rates Explained: Business, Medical, Moving, and Charity
IRS Notice 2026-10 publishes category-specific rates for 2026 and should be applied only after trip categorization and record validation.
Building a Mileage Reimbursement Policy with IRS and FAVR Rules
A defensible reimbursement policy requires explicit categories, source-linked rates, and routine record quality controls.
CAFE Public Information Center: A Practical Research Workflow
A source-first research workflow reduces status confusion in CAFE analysis and makes policy interpretation more reproducible.
CAFE vs EPA Emissions Standards: Why Two Federal Systems Exist
NHTSA CAFE and EPA emissions standards are related but distinct systems. Clear boundaries improve policy interpretation and planning decisions.
Deductible vs Nondeductible Miles: Business Driving Rules Explained
Mileage accuracy depends on trip classification first, then arithmetic. Category discipline is the foundation of defensible deduction math.
DOE’s 2026 Petroleum-Equivalent Fuel Economy Rule: What Changed
DOE published petroleum-equivalent fuel economy rule actions in January and February 2026. Reading both records together improves interpretation accuracy.
Federal and State Gasoline Taxes: How to Read EIA Tax Tables
Tax treatment is a structural part of fuel pricing, so tax context should be explicit in every cross-state comparison.
First-Year Rule for the Standard Mileage Method: What IRS Guidance Says
Method timing decisions can affect future flexibility. The first-year choice should be planned early, with records built to support the selected path.
Gasoline Price Components: Crude, Refining, Distribution, and Taxes
Retail gasoline is a composite price. Breaking it into components creates better budgeting decisions than headline-only interpretation.
How to Read the EIA Weekly Gasoline Price Update
EIA publishes recurring retail benchmarks that are useful for planning when interpreted as trend context, not same-day station guarantees.
IRS Mileage Log Requirements: What Counts as Adequate Records
Good mileage deductions start with good records. IRS guidance emphasizes adequate substantiation and consistent trip-level detail.
IRS Standard Mileage Rate vs Actual Expense Method (2026)
IRS guidance allows standard mileage and actual expense methods. Method choice should balance rules, records, and practical maintainability.
NEVI Minimum Standards: What Federal Funding Requires
NEVI requirements are best interpreted by pairing DOT summary material with Federal Register full-text rule language.
Refinery Data for Drivers: Reading the Weekly Supply Report
Weekly supply context can improve fuel-price interpretation when used as explanatory input, not as a one-release forecasting shortcut.
SAFE Vehicle Rule III Hearing Process: How Public Input Works
Hearing notices are process documents. Reading them correctly helps planners separate timeline signals from final technical requirements.
SAFE Vehicle Rule III: What the December 2025 Proposal Covers
The December 2025 Federal Register proposal describes suggested CAFE recalibration. Proposal status should be tracked separately from final-rule status.
State vs National Gas Price Data: An Apples-to-Apples Method
State and national series are both useful only when definition, timing, and tax treatment are aligned before interpretation.
Using the 2026 Fuel Economy Guide as a Research Dataset
The 2026 guide, downloadable files, and web services can be combined into a reproducible research pipeline with clear version controls.
Want to apply these concepts immediately? Use the Gas Mileage Calculator and compare against our FAQ reference as you track your own data.