The automotive toolbox
for mechanics & car owners
Free calculators, guided diagnostics, OBD-II codes and learning content — fast, mobile-first, installable as an app, and respectful of your privacy. No signup. Ever.
Dacia Logan 2021
Most used tools
Quick access to the calculators drivers and mechanics reach for most.
Interactive Car Diagnostic
Answer guided questions to narrow down why your car is behaving badly.
Open tool →Battery Calculator
Estimate battery health from open-circuit voltage and estimate runtime.
Open tool →Tire Calculator
Decode tire sizes and compare two sets with speedometer impact.
Open tool →Fuel Consumption Calculator
L/100 km, MPG, trip cost with fuel price and tolls.
Open tool →Garage Quote & Invoice Generator
Build professional estimates and invoices, then export as PDF.
Open tool →OBD-II Code Lookup
Search thousands of diagnostic trouble codes with causes and fixes.
Open tool →All 50 free tools
Diagnostics, electrical, engine, brakes & tires, fuel, transmission and garage tools — grouped by category.
Diagnostics
Interactive Car Diagnostic
Answer guided questions to narrow down why your car is behaving badly.
Air Conditioning Diagnostic
Step-by-step guide to find out why the AC is not cooling.
OBD-II Code Lookup
Search thousands of diagnostic trouble codes with causes and fixes.
OBD-II Live Scanner
Live RPM, speed, coolant and battery over Bluetooth with a BLE ELM327 adapter.
Photo Diagnostic Assistant
Photograph a tire, pad, disc or leak and follow an inspection checklist.
Sound Diagnostic Assistant
Record an engine noise and match it to likely causes.
Live OBD PID Data
Real-time engine data with charts — RPM, speed, coolant, MAF, load and battery analysis.
OBD Protocol Compatibility
Find which OBD protocol your vehicle uses — CAN, KWP2000, J1850 and more.
VIN Decoder & Vehicle Profile
Decode any VIN into make, model, year, engine, plant and specs — then jump straight to the right tools for that car.
Safety Recall Check
Search official safety recalls for a car by make, model and year — or by VIN — and see the fault, the risk and the free remedy.
Electrical
Battery Calculator
Estimate battery health from open-circuit voltage and estimate runtime.
Charging System Check
Analyze alternator and charging voltage with the engine off, idling and loaded.
Wire Gauge & Voltage Drop Calculator
Pick the right cable section (mm² / AWG) for a run from current, length and acceptable voltage drop — with ampacity and fuse sizing.
Engine
Oil Change Calculator
Oil quantity, service interval, filter and full service checklist.
Torque Specs Lookup
Search verified tightening torque values for common components.
Spark Plug Calculator
Replacement interval, cost and a quick misfire symptom assistant.
Cooling System & Coolant
Overheating diagnostic tree and coolant mix calculator.
Engine Compression Calculator
Theoretical compression ratio from bore, stroke and chamber volume.
Engine Builder Calculator
Displacement, piston speed and power estimates from bore and stroke.
Power & Torque Converter
Convert kW ↔ hp, Nm ↔ lb-ft and derive torque from power at RPM.
Oil Change Specs
Exact oil quantity, viscosity and filter for your car model and engine.
Brakes & Tires
Tire Calculator
Decode tire sizes and compare two sets with speedometer impact.
Wheel Diameter Calculator
Total diameter, circumference and distance per revolution.
Wheel Offset & Fitment
Convert offset and backspace, and see how a new wheel changes inner clearance and poke.
Tire Pressure Converter
Convert PSI, bar, kPa and kg/cm², and adjust the target for temperature and altitude.
Tire Age / DOT Decoder
Decode the DOT date code to find the manufacturing week, year and true age of a tire.
Brake Calculator
Disc thickness, pad wear alerts and replacement cost estimate.
Fuel & Economy
Fuel Consumption Calculator
L/100 km, MPG, trip cost with fuel price and tolls.
Fuel Log & Consumption Tracker
Track every fill-up and get your real L/100 km, cost per km, average price and CO₂ — stored privately on your device.
Transmission
Gearbox & RPM Calculator
RPM ↔ speed, gear ratio and final drive impact on your car.
Clutch & Gearbox Estimator
Estimate clutch wear from mileage and symptoms, plan the gearbox oil service (MTF/ATF/CVT/DCT) and price the replacement.
Garage & Billing
Garage Quote & Invoice Generator
Build professional estimates and invoices, then export as PDF.
Repair Cost Calculator
Real cost, margin and client price for any repair job.
Parts Margin Calculator
Set different margins for retail and professional customers.
Labor Cost Calculator
Time × hourly rate, plus parts and extras for the full bill.
Customer Manager
Client cards, linked vehicles and service history — stored only on your device.
Digital Service Book
VIN, mileage and full maintenance history per vehicle.
Service Reminders
Push notifications when an oil change or service comes due.
Vehicle Dashboard
A live status board per vehicle, computed from your service book.
Garage Dashboard
Revenue, accepted quotes, most profitable work and clients at a glance.
Parts Inventory
Track part stock with low-stock alerts and stock value.
Voice Assistant
“Create a quote for brake pads” — spoken commands become actions.
Photo → Quote
Photo of the car → confirm works → parts + labor → quote PDF.
Diagnostic Report Generator
Build a printable diagnostic report from a code or symptom with findings and checks.
Learn
Maintenance Checklist
Interactive 10,000 km service checklist you can tick on your phone.
Mechanic Quiz
Test your automotive knowledge and learn with explanations.
Which Tool Do I Need?
Pick an operation and get the exact tools, steps and safety warnings.
Mechanic Training
6 levels of interactive lessons and quizzes — from fundamentals to advanced.
AI Mechanic Assistant
13 free AI tools: mechanic chat, OBD explainer, photo inspection, voice commands, trip planning and more.
Car Programming & Tuning
ECU tuning, module coding, keys/immobilizer, gains calculator, coding logbook and tuning glossary.
Learn it in minutes
Practical guides with clear steps — from checking your oil to reading the check engine light.
How to Improve Diesel Engine Fuel Economy: Practical Tips for Better Efficiency
Diesel engines are inherently efficient, but poor driving habits and neglected maintenance can quickly drain your wallet at the pump. Whether you drive a light-duty pickup or a commuter car, making small adjustments to how you drive and car...
Read the guide →Diesel Engine Maintenance Checklist: How to Extend Engine Life and Improve Reliability
Diesel engines reward consistent care with long service life and fewer breakdowns. The checklist below covers the routine items a driver can handle or monitor, but always verify torque values and fluid specifications in your vehicle manual...
Read the guide →Diesel Engine Overheating: Causes, Warning Signs, and Repair Solutions
Diesel engines generate immense heat during combustion. While built tough to handle high compression, a failing cooling system can quickly cause catastrophic damage. Catching heat issues early keeps your truck running smoothly and saves you...
Read the guide →Black, White, or Blue Diesel Exhaust Smoke: Causes, Diagnosis, and Solutions
Diesel exhaust color can tell you a lot about what is happening inside an engine. Black, white, and blue smoke each point to different problems, and noticing the color early can save you from a costly repair. This guide explains the common...
Read the guide →Diesel Fuel Injectors: How They Work, Failure Symptoms, and Testing Methods
Diesel fuel injectors deliver precise amounts of atomized fuel directly into the combustion chamber under extreme pressures. In modern common rail systems, these components open and close multiple times per power stroke. Proper injector ope...
Read the guide →diesel engine won't start, diesel starting problems, diesel diagnosis
A diesel engine needs three things to start: enough cranking speed, fuel delivered at the right time and pressure, and air compressed hot enough to ignite that fuel. When one of these is missing, the engine will crank but not fire, or it ma...
Read the guide →Install AutoTools like an app
Open the menu in your browser and choose "Add to Home Screen". AutoTools then launches full-screen like a native app and several tools keep working offline.
Learn more