Make vehicle decisions with auditable numbers
Plan fuel, finance, tyres, EV charging and ownership costs with calculators that show the formula, worked example, assumptions and limits behind the result.
Browse tools by category
Choose a topic to find the right calculator quickly.
Fuel & Mileage Tools
9 tools · Calculate fuel use, economy, range and the real cost of driving.
Road Trip Tools
3 tools · Plan fuel stops, shared expenses and complete journey costs.
Car Finance Tools
6 tools · Explore payments, interest, affordability and ownership costs.
Tyre & Wheel Tools
4 tools · Compare tyre sizes, pressure units, offset and speed changes.
EV Tools
5 tools · Estimate charging time, electricity cost and usable range.
Engine & Performance
6 tools · Convert power and torque or compare performance ratios.
Maintenance & Ownership
4 tools · Budget servicing and understand monthly or annual running costs.
Automotive Converters
4 tools · Quick, correct conversions for speed, distance and temperature.
How the numbers are built
We separate fixed conversions from estimates so you can tell what is exact and what depends on assumptions.
1. Show the relationship
Each calculator states the formula or conversion constant used instead of hiding the arithmetic behind a result box.
2. Test with real inputs
Worked examples make unit mistakes easier to spot and show how a change in one assumption moves the result.
3. Explain the limit
Finance, range, depreciation and maintenance outputs are scenarios. Safety-critical choices still belong with official vehicle guidance.
Popular calculators
Useful starting points for common vehicle questions.
Fuel Cost Calculator
Estimate the fuel cost of a journey from distance, economy and pump price.
MPG Calculator
Find miles per US or Imperial gallon from trip records.
Car Loan Calculator
Estimate monthly car payments, interest and total repayment.
Tyre Size Calculator
Decode a tyre size and calculate its dimensions.
EV Charging Cost Calculator
Estimate the electricity cost of charging an EV.
Trip Cost Calculator
Add fuel, tolls, parking, food and lodging for a trip total.
Car Depreciation Calculator
Estimate future vehicle value using annual depreciation.
MPH and KM/H Converter
Convert road speed between miles per hour and kilometres per hour.
Popular automotive guides
Understand the assumptions behind the numbers.
How to Calculate Fuel Cost for a Trip
Estimate a trip’s fuel bill from distance, economy and the pump price.
What Is Good MPG?
Compare your car’s MPG fairly by class, route, fuel type and real driving conditions.
MPG vs KM/L Explained
Switch between MPG and km/L while keeping US and Imperial gallons straight.
How Fuel Economy Is Calculated
Measure real fuel economy from an odometer reading and a full-tank fill-up.
How to Read a Tyre Size
Decode tyre width, profile, rim size and the ratings that affect fitment.
What Does 225/45R17 Mean?
See exactly what 225/45R17 means and calculate its nominal diameter.
Common questions
Are these automotive calculators free?
Yes. Every public calculator and converter can be used without creating an account.
How accurate are the results?
Unit conversions follow fixed constants. Costs, range, depreciation and maintenance results are estimates because real conditions and prices vary. Each tool explains its assumptions.
Does UK MPG differ from US MPG?
Yes. An Imperial gallon is larger than a US gallon. Tools involving MPG label the standard and apply the correct factor.