Flight Radiation Calculator
Estimate the cosmic radiation dose of any flight from its duration, cruise altitude, and route latitude — with 15 ready-made routes and everyday comparisons.
Flying does not create radiation — it removes shielding
Cosmic rays hit the atmosphere constantly. At sea level roughly ten tonnes of air sit above every square metre and absorb almost all of it. At 37,000 feet three quarters of that shield is below you, so the dose rate is around a hundred times higher.
Pick a route or enter your own flight. Latitude matters as much as altitude, because Earth's magnetic field deflects far more of the incoming particles near the equator than near the poles.
How to use the flight radiation calculator
- Pick a route or build your own: the presets fill in a typical flight time, cruise altitude, and average latitude, all of which stay editable.
- Set the cruise altitude: feet, metres, or flight level. This is the single strongest lever in the calculation — the dose rate roughly doubles every 6,000 ft.
- Enter the average latitude of the route: a Singapore–Jakarta hop sits near 5°, a Chicago–Beijing polar crossing near 65°, and that difference alone changes the answer by a factor of two.
- Choose where the solar cycle is: doses run highest at solar minimum and lowest at solar maximum, because an active Sun deflects galactic cosmic rays.
- Count your legs: use 2 for a return trip, or add up a year of flying to see how a travel habit compares with natural background radiation.
Formula: how flight radiation dose is calculated
A flight radiation calculator estimates the cosmic radiation dose received during an airplane flight. It calculates exposure using factors such as flight altitude, duration, route, and solar activity. Radiation exposure generally increases at higher altitudes and on routes closer to the poles because atmospheric shielding and Earth's magnetic protection decrease.
Mechanically, all of that collapses into a dose rate multiplied by a time. The rate is the hard part, because it carries the altitude, geomagnetic latitude, and solar dependence; the time is simply how long you spend up there. In symbols, D = Ṙ × t, where Ṙ is the effective dose rate in microsieverts per hour and t is the hours flown.
This page builds the dose rate from published anchor points rather than from a single fixed number. Aviation dosimetry work summarised by the FAA puts the rate at 35,000 ft over high latitudes at roughly 6 µSv/h, and at 41,000 ft at roughly 12 µSv/h — a doubling across 6,000 ft. That gives a clean exponential in altitude, which the calculator then scales for latitude and for the solar cycle.
D = Ṙ × t
Ṙ = 6 µSv/h × 2(h − 35,000 ft) / 6,000 ft × flat × fsol
flat = 0.5 + 0.5 × min(1, (φ / 55°)²)
The latitude term encodes a well-documented observation: at cruise altitude the dose rate over the poles is about twice the dose rate over the equator, and the effect saturates once you are past roughly 55°, because beyond that the magnetic field lines are already close to vertical and offer almost no deflection.
The solar term is a multiplier of 1.15 at solar minimum, 1.00 at cycle average, and 0.75 at solar maximum. Climb and descent are handled by treating about 40 minutes of the flight as spent well below cruise level, at roughly 40% of the cruise rate.
For example, a 7-hour flight at 37,000 ft along a 55° route at cycle average gives 6 × 2^(2000/6000) = 7.6 µSv/h, and a total of about 50 µSv — half a chest X-ray.
Dose rate reference: the FAA advisory material on radiation exposure in the aviation environment sets out the altitude and latitude dependence used here, including the roughly two-to-one pole-to-equator ratio.
Cosmic radiation dose rate by altitude and latitude
Effective dose rate in microsieverts per hour at solar cycle average, from the model used on this page. The last column shows what a ten-hour flight at that altitude would deliver on a high-latitude route.
| Cruise altitude | Equator (0°) | Subtropical (30°) | High / polar (55°+) | 10 h at 55°+ |
|---|
What a flight dose actually compares to
Sieverts are unfamiliar units, so the numbers only mean something next to doses people already have opinions about. Everything below is an effective dose in millisieverts, which is the quantity that lets radiation from different sources be added up sensibly.
| Source | Typical effective dose | In flight terms |
|---|---|---|
| Eating one banana | 0.0001 mSv | About a minute at cruise altitude. |
| Dental X-ray | 0.005 mSv | Roughly a short domestic hop. |
| Chest X-ray | 0.1 mSv | Around two transcontinental flights. |
| Cosmic radiation at ground level, one year | 0.33 mSv | Six or seven long-haul flights. |
| All natural background, one year | ≈ 3 mSv | Roughly sixty transatlantic crossings. |
| Abdominal CT scan | ≈ 8 mSv | More than a hundred long-haul flights. |
| Occupational annual limit, radiation workers | 20 mSv | Far above any realistic passenger total. |
Why airport security barely registers: the millimetre-wave scanners used for passengers do not use ionising radiation at all, and backscatter X-ray units, where still in use, deliver something on the order of a fraction of a microsievert — less than a minute of the flight you are about to take.
Comparison figures: the CDC's page on radiation from air travel notes that two transcontinental trips are about equal to one chest X-ray, and that cosmic radiation contributes roughly 0.33 mSv a year whether or not you fly.
How much does a year of flying add up to?
A single flight is easy to dismiss. The question people actually want answered is whether their travel habit adds up to anything. These profiles are run through the same model as the calculator above, so the numbers are directly comparable with any result you generate.
| Traveller or crew profile | Flying pattern | Annual dose | In context |
|---|
Leisure flying barely registers
Two holidays a year lands near 0.05 mSv — under 2% of natural background, and less than the difference between living at sea level and living in a mountain town.
Heavy business travel is where it turns
Around fifteen to twenty long-haul legs a year, a frequent flyer's exposure passes the 1 mSv annual figure that ICRP and NCRP use as a public dose limit — a threshold no passenger is actually held to, but a useful marker. Beyond that, a heavy corporate travel schedule overlaps with real cabin crew rosters.
Crew are in a different bracket
Block hours, not trips, drive crew totals. A long-haul polar roster of several hundred hours lands near 6 mSv a year, which is the figure the IAEA quotes and the point at which EU rules escalate.
A caution on the public dose limit: the 1 mSv a year figure applies to deliberate, controlled sources of exposure. Natural background and medical imaging are both excluded from it, and so, in practice, is flying — no jurisdiction caps how much a passenger may fly. It is a yardstick for scale, not a rule anyone is breaking.
What changes the dose, and by how much
Four variables do nearly all the work. Two of them you cannot control as a passenger, one you notice only across years, and one is simply how much you fly.
| Factor | Approximate effect | Why |
|---|---|---|
| Time in the air | Directly proportional | Dose accumulates every hour you stay at altitude. |
| Cruise altitude | Doubles per ~6,000 ft | Less air overhead means less of the cosmic ray shower is absorbed. |
| Latitude of the route | Up to 2× from equator to pole | The geomagnetic field deflects charged particles best near the equator. |
| Point in the solar cycle | Roughly ±20–30% | A stronger solar wind sweeps galactic cosmic rays out of the inner solar system. |
| Solar particle events | Rare, occasionally large | Big flares can briefly raise high-latitude doses; airlines reroute or descend. |
| Seat, cabin class, aircraft type | Negligible | An aluminium fuselage barely attenuates high-energy secondaries. |
The counterintuitive one: people expect a stormy Sun to mean more radiation on board. For routine flying the opposite holds — dose rates peak at solar minimum, when the quiet solar wind lets more galactic cosmic rays reach Earth.
Two quick examples
Transatlantic, 7 h at 37,000 ft, 55°
7.6 µSv/h × 6.3 h at cruise plus a low-altitude climb and descent ≈ 50 µSv, or 0.05 mSv. Half a chest X-ray, and about 1.7% of a year's natural background.
Equatorial hop, 1.5 h at 35,000 ft, 5°
3.0 µSv/h over a short sector ≈ 3 µSv. Less than a dental X-ray, and roughly thirty bananas' worth of potassium-40.
Interesting fact: aircrew are among the most exposed workers on the ground payroll
Studies of United States flight attendants and pilots put annual doses in the range of roughly 0.2 to 5 mSv depending on route patterns, which puts aircrew at the top of the table of monitored occupational groups — above the average for radiation workers in medicine and the nuclear industry, whose average annual dose equivalent has been estimated at about 1.1 mSv. The oddity is that most of those nuclear and medical workers wear dosimeters and appear in a dose registry, while in the United States crew exposure to natural cosmic radiation is generally neither regulated nor routinely monitored. In the European Union the position is different: operators must assess exposure where it is likely to exceed 1 mSv a year and manage rosters so that individuals stay well below occupational limits.
Source: IAEA — Aircrew and Space Crew, which gives 6 mSv a year as a typical figure for long-haul polar crews against a 20 mSv occupational limit.
Radiation limits and rules that actually apply in the air
Once you have a number, the obvious next question is what it is measured against. The answer differs by jurisdiction and by who you are: passengers are governed by nothing at all, US crew by recommendations, and EU crew by binding law with escalating tiers.
| Who | Where | Figure | What it triggers |
|---|---|---|---|
| Passengers | Everywhere | No limit | Nothing. No authority caps passenger flying, and no airline tracks your cumulative dose. |
| General public | ICRP / NCRP guidance | 1 mSv per year | A reference level for controlled sources. Natural background, medical imaging, and flying sit outside it. |
| Aircrew | United States (FAA AC 120-61B) | 20 mSv/yr averaged over 5 years, max 50 mSv in any one year | Recommended, not regulatory. Crew exposure is generally neither monitored nor recorded. |
| Aircrew | EU (2013/59/Euratom) | Liable to exceed 1 mSv/yr | Operator must assess individual exposure, inform the crew member, and take dose into account when building rosters. |
| Aircrew | EU (2013/59/Euratom) | Liable to exceed 6 mSv/yr | Managed as a planned exposure situation, with the fuller monitoring and health surveillance regime that implies. |
| Pregnant crew, after declaration | US guidance (NCRP) | 0.5 mSv per month, 1 mSv for the remainder | Roster adjustment; flying typically continues within the monthly ceiling. |
| Pregnant crew, after declaration | EU and UK | 1 mSv to the fetus for the remainder | Same headline figure, stricter application — UK practice has been to remove crew from flying duties on declaration. |
The same number, two different outcomes: the US and European figures for pregnancy look almost identical on paper, yet they are applied so differently that a pregnant crew member may keep flying under one regime and be grounded on the day she declares under the other. If you are crew, the number that matters is the one your operator is legally working to, not the lowest one you can find online.
Primary texts: FAA Advisory Circular 120-61B, In-Flight Radiation Exposure, and the EU's Council Directive 2013/59/Euratom, which sets the 1 mSv and 6 mSv aircrew tiers.
How to interpret the results
This is a model, not a dosimeter
Professional route dose codes such as CARI and EPCARD track the actual flight profile, geomagnetic cutoff along the path, and real-time solar data. Treat this output as an order-of-magnitude estimate, good to within a few tens of percent.
Route latitude is an average, not a destination
Great-circle tracks run far north of what a flat map suggests. London to Los Angeles crosses Greenland, so its average latitude is much higher than either endpoint.
Effective dose is already a risk-weighted quantity
Sieverts fold in how damaging each particle type is, which matters in flight because neutrons carry a large share of the dose. That is why in-flight numbers can be added to medical doses at all.
Getting a more accurate number for your own flight
This calculator is deliberately simple. If you need a defensible figure — for a crew logbook, an occupational health conversation, or a pregnancy question — there are two things to improve: feed better inputs into a model like this one, or skip to a professional route dose code.
Four inputs worth getting right
- Use the real cruise altitude, not the aircraft's ceiling. A flight tracking app shows the actual flight level flown, and long sectors usually step-climb as fuel burns off — a flight that starts at FL330 may finish at FL390, roughly a 40% higher dose rate. Splitting a long flight into two calculations and adding them beats guessing an average.
- Take the latitude from the track, not the airports. Great-circle routes bend poleward. London to Los Angeles crosses Greenland at close to 65°, nowhere near either endpoint. Use the highest-latitude portion of the track for a conservative figure, or the midpoint of the northern leg for a typical one.
- Use airborne time, not scheduled block time. Published schedules include taxi, and long taxi times at busy hubs can inflate a short sector's apparent dose by ten percent or more.
- Check where the solar cycle actually is. The difference between solar minimum and maximum is 20–30%, which is larger than most people's error in guessing altitude. Sunspot number is the quickest proxy.
The professional route dose codes
These integrate along the real flight path using geomagnetic cutoff rigidity and measured heliospheric data. Model intercomparison studies have found the main codes agree with each other and with in-flight measurements to within roughly 25%, which is about as good as this field gets.
| Code | Maintained by | What it adds over a simple estimate |
|---|---|---|
| CARI-7A | FAA Civil Aerospace Medical Institute, US | Full particle transport rather than the older superposition shortcut; the de facto reference for US crew dose work. |
| NAIRAS | NASA Langley, US | A now-cast: global dose rate maps driven by current satellite and ground data, rather than a climatological average. |
| EPCARD | Helmholtz Zentrum München, Germany | Long-established European code used for regulatory crew dose assessment. |
| SIEVERT | French civil aviation authority and IRSN | Operator-facing system built for reporting individual crew doses under EU rules. |
| PANDOCA / AVIDOS / JISCARD EX | DLR (Germany), Seibersdorf (Austria), JAEA (Japan) | National equivalents, each validated against the same body of in-flight measurements. |
When a simple estimate is not enough: during a solar particle event, no climatological model — including this one — is meaningful, because the dose rate is being set by an event that has not happened yet in the model's data. That is what the now-cast systems and space weather radiation alerts exist for, and it is the one situation where operators actively change altitude or routing in response.
Further reading on measured crew doses and how the codes are used in practice: the Health Physics Society's expert answers on radiation exposure during commercial airline flights.
Frequently Asked Questions
How much radiation do you get on a flight?
A seven-hour transatlantic flight at 37,000 ft works out at roughly 0.05 millisieverts, or 50 microsieverts — about half a chest X-ray. A one-hour domestic sector is usually under 0.01 mSv, while a fourteen-hour polar long-haul can reach 0.12 mSv or a little more. Four things move the number: flight duration, the altitude the airplane actually cruises at, how far the route runs from the equator, and where the solar cycle happens to sit. The calculator above lets you change all four and watch the dose rebuild itself, which is more informative than any single average figure.
What is the radiation dose rate at cruising altitude?
At 35,000 ft over high latitudes the cosmic radiation dose equivalent rate is about 6 microsieverts per hour, and by 41,000 ft it roughly doubles to about 12 microsieverts per hour. Over the equator at the same altitude it is roughly half those figures. On the ground in the contiguous United States the combined cosmic and terrestrial rate averages about 0.06 microsieverts per hour, which is where the familiar line about a hundred times more radiation up there comes from. Nothing about the aircraft itself generates this exposure — the aeroplane has simply climbed above most of the atmosphere that normally absorbs the particle shower.
Is flying radiation dangerous for passengers?
For ordinary travel the doses are small enough that public health agencies describe the health risk to passengers as negligible. Even a heavy leisure travel year — say twenty long-haul legs — lands near 1 millisievert, roughly a third of what a person receives annually from natural background regardless of whether they ever board an airplane. The comparison worth keeping in mind is that where you live changes your background exposure by more than most people's flying does: altitude of residence, local geology, and indoor radon all swamp the contribution from a few flights a year.
Why does latitude change the radiation dose on a flight?
Cosmic radiation is mostly charged particles, and charged particles are steered by magnetic fields. Near the equator Earth's field lines run parallel to the surface and act like a barrier, so only the highest-energy particles get through to the atmosphere below. Near the poles those lines are close to vertical and lead straight in. The practical result is that at the same altitude a polar route sees roughly twice the dose rate of an equatorial one, and the effect stops growing above about 55° of latitude because the deflection there is already minimal. This is why two flights of identical duration can differ in exposure by a factor of two.
Does solar activity increase or decrease flight radiation?
Routine doses go down when the Sun is active. Strong solar activity inflates the heliosphere and sweeps galactic cosmic radiation away from the inner solar system, so dose rates peak at solar minimum and bottom out near solar maximum, a swing of roughly 20–30%. The exception is a large solar particle event, which can push high-latitude dose rates up sharply for a few hours; carriers respond to radiation alerts by having the crew descend to a lower altitude or reroute the aircraft away from polar tracks, both of which cut the exposure quickly.
How much radiation do pilots and flight attendants receive?
Published assessments put annual aircrew exposure at roughly 0.2 to 5 millisieverts depending on the routes flown, with long-haul polar rosters at the high end. That is enough to place pilots and cabin crew among the most exposed monitored occupational groups, though still below the 20 mSv annual limit applied to radiation workers generally. Flight deck and cabin crew receive essentially the same dose, since no part of the aircraft offers meaningful shielding. Where a health risk is discussed for crew, it concerns cumulative exposure over a career of high flight hours rather than any single flight.
Is flying safe during pregnancy from a radiation point of view?
Occasional passenger flying delivers doses far below the guidance figures used in pregnancy, which are typically 1 millisievert across the whole term or 0.5 mSv in any month. A handful of long-haul trips does not come close. Frequent flying for work is a different question — a crew member on high-dose polar routes could approach a monthly guideline — which is why several regulators require exposure assessment and roster adjustment. Anyone weighing this in a specific pregnancy should raise it with their doctor or occupational health service rather than rely on a general-purpose calculator.
Do airport scanners add much radiation?
Barely. The millimetre-wave body scanners in general use emit non-ionising radio-frequency energy and contribute nothing to a passenger's dose. Backscatter X-ray units, where they are still deployed, give a fraction of a microsievert per scan — less exposure than the airplane delivers while it is still taxiing. Checked-baggage machines irradiate the bag, not the traveller. Against a flight measured in tens of microsieverts, security screening is a rounding error.
Can you reduce your radiation dose while flying?
Not in any way worth doing as a passenger. Seat choice, cabin class, window versus aisle, and aircraft type make no meaningful difference, because an aluminium fuselage does not stop the high-energy neutrons and secondaries that carry most of the dose at altitude. The only real levers are flying less, choosing shorter flight durations, and — in principle — lower-altitude, lower-latitude routes, none of which a passenger gets to choose. Supplements marketed to frequent flyers as radiation protection have no established benefit at these exposure levels.
Why might another flight radiation calculator give a different answer?
Mostly because of the assumptions behind the dose rate. Some tools apply one fixed rate to every flight, some assume a single cruise altitude, and some ignore latitude entirely — which alone can shift the result by a factor of two. Others run a full route dose code with the real great-circle track and live solar activity data, and will be more accurate than any simplified model. This calculator prints the rate, the altitude, the latitude factor, and the solar factor behind every result, so a difference against another estimate can be traced to the assumption that caused it rather than left as a mystery.
Data sources and assumptions
Dose rates are anchored to published aviation dosimetry figures: about 6 µSv/h at 35,000 ft and about 12 µSv/h at 41,000 ft at high latitude, a pole-to-equator ratio near two to one, and a solar cycle modulation of roughly 20–30%. Comparison doses use commonly cited effective dose values for medical imaging and natural background.
- CDC: Facts About Radiation from Air Travel — what drives passenger dose, and the chest X-ray and annual cosmic dose comparisons.
- FAA: Exposure to Radioactive Materials in the aviation environment — cruise-altitude dose rates and the geomagnetic latitude dependence.
- IAEA: Aircrew and Space Crew — typical aircrew annual doses, natural background averages, and occupational limits.
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