Last reviewed and updated:
This page gathers every free USFITools aviation calculator and guide in one place, organised by ground school subject. Student pilots can use it to check homework and practise exam-style sums; instructors and flight schools are welcome to share it with their students. Every tool is free, works on a phone and needs no sign-up, and every tool shows its formula so students learn the method, not just the answer.
Meteorology
| Tool or guide | What it helps with |
|---|---|
| METAR & TAF Weather | Live, decoded reports for any airport |
| How to Read METAR and TAF | Decoding codes line by line |
| ISA Standard Atmosphere Calculator | ISA temperature, pressure and deviation |
| ISA Explained | Values to memorise and exam practice |
| Cloud Base Calculator | Cloud base from temperature and dew point |
Aircraft performance and loading
| Tool or guide | What it helps with |
|---|---|
| Density Altitude Calculator | Hot-day and high-airfield performance |
| Density Altitude Explained | Why hot and high days are dangerous |
| Pressure Altitude Calculator | Pressure altitude from elevation and QNH |
| Weight and Balance Calculator | Moments and centre of gravity |
| Weight and Balance Guide | Working through a loading sheet |
| Aviation Fuel Weight Converter | Avgas and Jet A-1 litres, gallons, kg, lb |
| Aviation Fuel Weight Guide | Densities and fuel traps |
| Crosswind & Headwind Calculator | Wind components against aircraft limits |
| Crosswind Components Explained | Trigonometry and the clock-face rule |
| Climb Gradient Calculator | ft/NM to ft/min for departures |
Navigation and flight planning
| Tool or guide | What it helps with |
|---|---|
| Time, Speed & Distance (E6B) | Leg times, ground speed, fuel and ETA |
| E6B Basics for Student Pilots | Formulas and mental shortcuts |
| Wind Correction Angle Calculator | Heading and ground speed from the wind |
| True Airspeed Calculator | IAS to TAS for altitude and temperature |
| 1 in 60 Rule Calculator | Off-course corrections |
| The 1 in 60 Rule Explained | Track error, closing angle, drift lines |
| Aviation Fuel Calculator | Trip fuel and reserves |
| Descent Rate Calculator | Top of descent and rate of descent |
| Nautical Miles Converter | NM, km and statute miles |
| Coordinate Converter | Decimal and degrees-minutes-seconds |
| Airport Code Lookup | ICAO and IATA codes |
Instrument flying
| Tool or guide | What it helps with |
|---|---|
| Holding Pattern Entry Calculator | Direct, teardrop or parallel entry |
| Holding Pattern Entries Explained | Sector rule and a quick lookup table |
| Climb Gradient Explained | Meeting departure procedure gradients |
| QNH hPa / inHg Converter | Altimeter setting units |
| QNH, QFE and QNE Explained | Altimeter settings and flight levels |
Time, logbook and daylight
| Tool or guide | What it helps with |
|---|---|
| UTC / Local Time Converter | Zulu time with date rollover |
| Zulu Time and UTC in Aviation | Why aviation uses UTC |
| Flight Hours Calculator | Decimal and logbook time |
| Sunrise, Sunset & Civil Twilight | Daylight limits for VFR flights |
| Feet / Metres Converter | Altitudes and runway lengths |
For flight schools and instructors
If these tools are useful to your students, you are welcome to link to this page from your student resources, ground school notes or learning portal. Corrections and suggestions for new tools are always welcome through our contact page.
All tools are for training and general information. Students should follow their instructor’s guidance, their aviation authority’s rules and the approved data for their aircraft.
Sources and further reading
- FAA Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25)
- FAA Airplane Flying Handbook (FAA-H-8083-3)
- FAA Instrument Flying Handbook (FAA-H-8083-15B, PDF)
- FAA Aviation Handbooks and Manuals (includes the Aviation Weather Handbook, FAA-H-8083-28)
- FAA Aeronautical Information Manual (AIM)
Sources checked November 2026. Rules differ between countries and change over time: for real flights, use the current publications of the authority that applies to you, your aircraft flight manual and your operator’s procedures.