At cruising altitude there is less atmosphere above you to absorb cosmic radiation, so the dose rate is roughly 100 times higher than on the ground. A single flight gives a very small dose – a transatlantic trip is comparable to a chest X-ray – but frequent flyers and aircrew accumulate measurable yearly doses.
How to use the Flight Radiation Calculator
- Flight time
- Route
- Custom dose rate
- Number of such flights per year
- Every result field is editable: type into Dose for this flight and Flight time plus every other field update to match.
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the flight time and pick a route type (or enter your own dose rate). Type a dose into the result to find how many flight hours it corresponds to.
Tips
- Use your own measured figures – fuel economy, speed and prices vary a lot with driving style, traffic, load and season.
- Pick the unit in each field’s menu (miles or kilometres, mpg or L/100 km); the calculator converts everything for you.
- Fill up to the brim twice and divide the distance by the fuel added to measure real fuel economy.
- For vehicle modifications, treat results as a starting point and confirm with the parts maker or a professional mechanic.
Common mistakes to avoid
- Mixing US and imperial (UK) gallons – a UK gallon is about 20% bigger.
- Using the advertised fuel economy instead of real-world figures.
- Forgetting tolls, parking and wear and tear when comparing driving with public transport.
Inputs explained
| Field | What to enter |
|---|---|
| Flight time | In h |
| Route | Choose one: Typical long-haul, mid-latitudes (0.003 mSv/h), Short-haul, lower altitude (0.0015 mSv/h), High-latitude long-haul (0.005 mSv/h), Polar route (0.008 mSv/h) … |
| Custom dose rate | In mSv/h |
| Number of such flights per year | A number |
What each result means
- Yearly dose from these flights = [Dose for this flight]×[Number of such flights per year]
- Share of average yearly background (2.4 mSv) = [Yearly dose from these flights]÷2.4×100
- Equivalent chest X-rays (0.1 mSv each) = [Dose for this flight]÷0.1
Example values
How the main result changes when Flight time changes and everything else stays at the example values above:
| Flight time (h) | Dose for this flight (mSv) |
|---|---|
| 3.5 | 0.0105 |
| 5.25 | 0.0158 |
| 7 | 0.021 |
| 8.75 | 0.0263 |
| 10.5 | 0.0315 |
| 14 | 0.042 |
Formula
Dose = flight time × dose rateTypical dose rates: 0.002–0.005 mSv/h at cruising altitude, up to about 0.008 mSv/h on polar routesWorked example
Inputs — Flight time: 7 h; Route: Typical long-haul, mid-latitudes (0.003 mSv/h); Custom dose rate: 0.004 mSv/h; Number of such flights per year: 10.
Results — Dose for this flight = 0.021 mSv; Yearly dose from these flights = 0.21 mSv; Share of average yearly background (2.4 mSv) = 8.8 %; Equivalent chest X-rays (0.1 mSv each) = 0.21.
Frequently asked questions
Is flying a radiation risk?
For passengers the dose is small; even 100 hours a year adds about 0.3 mSv, a fraction of natural background.
Do pilots get more radiation?
Aircrew receive about 1–5 mSv a year and are classified as occupationally exposed in many countries.
Do airport scanners add radiation?
Millimetre-wave scanners use no ionising radiation; backscatter X-ray scanners give a tiny dose of about 0.0001 mSv.
What formula does the Flight Radiation Calculator use?
Dose = flight time × dose rate.