Cosmic radiation on flights from New York (JFK) to Paris (CDG)

Reverse: Paris → New York

A flight from John F. Kennedy International Airport to Charles de Gaulle International Airport at 35,000 ft, about 6 h 36 min in the air, receives about 0.0273 mSv (27.3 µSv) of cosmic radiation: about a quarter of a chest X-ray. That is the FAA's CARI-7 model run for this route with the solar conditions of August 2026.

Updated · solar conditions of August 2026

Dose
27.3 µSv0.0273 mSv
Time in the air
6 h 36 minestimated
Dose rate
4.1 µSv/haverage, 35,000 ft
Chest X‑rays
0.27at 0.1 mSv each

Key facts: JFK → CDG

Dose, standard flight0.0273 mSv (27.3 µSv)
Time in the air6 h 36 min, estimated from distance and prevailing winds
Cruise altitude35,000 ft
Average dose rate4.1 µSv/h
Great-circle distance5,833 km (3,624 mi)
Furthest from the equator52.4°N
Solar conditionsAugust 2026

The standard flight is CARI-7, the FAA Civil Aerospace Medical Institute's model, run on the dev machine for this route: 35,000 ft, 6 h 36 min in the air (climb 25 min, cruise 354 min, descent 17 min), effective dose per ICRP Publication 103. How it's calculated.

JFKCDG
Great-circle route, shaded from 3.7 µSv/h to 4.3 µSv/h. Shading is modelled from the monthly dose-rate grid; totals are CARI-7.

How the sun changes the dose on JFK → CDG

The sun's 11-year cycle moves this number. With the same 6 h 36 min at 35,000 ft, the flight would have received 0.0345 mSv in April 2020, when the sun was quiet and more galactic cosmic rays reached the atmosphere, and 0.0212 mSv in January 2026, near solar maximum: 63% more at the quiet end. In August 2026 it is 0.0273 mSv.

Dose for this flight at 35,000 ft, quarterly
0 µSv10 µSv20 µSv30 µSv40 µSv20162018202020222024202634.5 µSv21.2 µSv27.3 µSv
0 µSv10 µSv20 µSv30 µSv40 µSv20162020202434.5 µSv21.2 µSv27.3 µSv
The numbers behind the chart
MonthDoseDose
January 201630.3 µSv0.0302 mSv
April 201631.1 µSv0.0311 mSv
July 201631 µSv0.031 mSv
October 201632.1 µSv0.0321 mSv
January 201732.5 µSv0.0325 mSv
April 201733.3 µSv0.0333 mSv
July 201732.7 µSv0.0327 mSv
October 201732.4 µSv0.0324 mSv
January 201833 µSv0.033 mSv
April 201833.9 µSv0.0339 mSv
July 201833.7 µSv0.0337 mSv
October 201834.4 µSv0.0344 mSv
January 201932.7 µSv0.0327 mSv
April 201934.3 µSv0.0343 mSv
July 201933.8 µSv0.0338 mSv
October 201934.3 µSv0.0343 mSv
January 202034.1 µSv0.0341 mSv
April 202034.5 µSv0.0345 mSv
July 202034.2 µSv0.0342 mSv
October 202034.2 µSv0.0342 mSv
January 202133 µSv0.033 mSv
April 202134.3 µSv0.0343 mSv
July 202133.5 µSv0.0335 mSv
October 202133.6 µSv0.0336 mSv
January 202232.9 µSv0.0329 mSv
April 202232.6 µSv0.0326 mSv
July 202229.8 µSv0.0297 mSv
October 202230.7 µSv0.0307 mSv
January 202327.9 µSv0.0279 mSv
April 202328.3 µSv0.0283 mSv
July 202326.5 µSv0.0265 mSv
October 202326.7 µSv0.0267 mSv
January 202425.1 µSv0.0251 mSv
April 202425.8 µSv0.0258 mSv
July 202426.1 µSv0.0261 mSv
October 202422.5 µSv0.0225 mSv
January 202523.4 µSv0.0234 mSv
April 202523.4 µSv0.0234 mSv
July 202523.2 µSv0.0232 mSv
October 202523.8 µSv0.0238 mSv
January 202621.2 µSv0.0212 mSv
April 202624.3 µSv0.0243 mSv
July 202626.1 µSv0.0261 mSv
August 202627.3 µSv0.0273 mSv

How cruise altitude changes the dose

Flown at 31,000 ft instead, the same flight would receive 0.0198 mSv, 28% less than at 35,000 ft; at 41,000 ft it would receive 0.0398 mSv, 46% more. Same route, same time in the air, same month: only the air overhead changes.

Dose for this flight by cruise altitude, August 2026
  • 31,000 ft19.8 µSv
  • 33,000 ft23.4 µSv
  • 35,000 ft27.3 µSv
  • 37,000 ft31.4 µSv
  • 39,000 ft35.6 µSv
  • 41,000 ft39.8 µSv

Try it: change the altitude and the month

Every combination is its own CARI-7 run for JFK → CDG, with the same 6 h 36 min in the air. It is still a standard flight, not yours: the app calculates your exact flight.

Every combination as a table (µSv)
AltitudeJan 2016Jan 2017Jan 2018Jan 2019Jan 2020Jan 2021Jan 2022Jan 2023Jan 2024Jan 2025Jan 2026Aug 2026
31,000 ft21.823.423.723.524.523.823.720.218.21715.519.8
33,000 ft25.927.828.227.929.128.228.123.921.520.118.323.4
35,000 ft30.332.53332.734.13332.927.925.123.421.227.3
37,000 ft34.837.53837.739.438.137.932.128.826.824.231.4
39,000 ft39.542.643.342.944.843.343.236.432.530.327.335.6
41,000 ft44.447.948.748.250.548.748.540.736.333.830.439.8

The return flight: CDG → JFK

CDG → JFK receives 0.0319 mSv at 35,000 ft, 17% more than JFK → CDG, over about 7 h 37 min in the air against 6 h 36 min. The return takes 1 h 1 min longer: its track runs against the prevailing westerly winds at cruise altitude. Cosmic radiation builds up with every minute aloft, so the longer direction collects more of it along the same path.

Dose for each direction, standard flight
  • JFK → CDG27.3 µSv
  • CDG → JFK31.9 µSv

Cosmic radiation on Paris → New York flights

What 27.3 µSv compares with

Compared withIts doseThis flight is
Chest X-Ray0.1 mSvabout a quarter of a chest X-ray
Dental X-Ray0.005 mSvabout 5.5 dental X-rays
Background Radiation (Daily)0.008 mSvabout 3.4 days of natural background radiation
Mammogram0.4 mSvabout 7% of a mammogram
Head CT Scan2 mSvabout 1% of a head CT scan
Eating a Banana0.0001 mSvabout 274 bananas

The comparison values are the ones the FlightDose app uses.

Why your flight will differ

  • Altitude. Flown at 31,000 ft instead, the same flight would receive 0.0198 mSv, 28% less than at 35,000 ft; at 41,000 ft it would receive 0.0398 mSv, 46% more. Same route, same time in the air, same month: only the air overhead changes.
  • Time in the air. Every extra 30 minutes on this route adds about 2.1 µSv. Headwinds, holding and routing change it by tens of minutes on a long flight.
  • The month. The sun's 11-year cycle swings this route's dose by about 63% between quiet and active years.
  • The track. Airlines fly tracks that bend with the jet stream, not the exact great circle; a track further from the equator collects more.
  • Solar storms. A rare solar radiation storm can add to the dose for hours; CARI-7's monthly figures don't include one.

FlightDose calculates your exact flight.

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