Space Calculators

CME Arrival Time Calculator

Estimate a coronal mass ejection's transit time from the Sun to Earth, based on its launch speed and the real distance of 1 astronomical unit.

☄️ Interplanetary CME Arrival Time Calculator

Calculate estimated solar plasma shockwave travel timelines from the Sun's corona to Earth's magnetosphere boundary.

Launch Speed1,000 km/s

300 km/s (quiet filament eruption)3,500 km/s (extreme Carrington-class)

Estimated Transit: 1d 17h 33m

(41.6 total hours)

🟡 Fast CME

Can drive a strong (G2–G4) storm if its magnetic field points south on arrival, but many fast CMEs only produce minor storms. Aurora may reach mid-latitudes; radio and GPS disruption is possible.

This is a simple constant-speed estimate (1 AU divided by the speed you set). Real CMEs speed up or slow down toward the ambient solar wind (about 400-500 km/s), so fast ones usually arrive later than this number and slow ones sooner; even NOAA's forecasts carry roughly ±10 hours of uncertainty. It is a hypothetical calculator, not a live tracker of an actual, currently in-progress CME. For real, current solar activity, see our live CME tracker.