Barometric pressure change calculator
Enter two readings from the same source — a phone barometer or a weather app, not one of each. The calculator shows the rise or drop in both hPa and inches of mercury.
Log the change, not a theory
People who track weather with migraine usually mean a falling number, not a single “bad” pressure. About 5 to 10 hPa in a day is a practical size to circle in a diary. It is not a cutoff that proves the storm caused the pain, and a flat reading is not protection.
Phone sensors and a forecast for the nearest airport can disagree by a few hPa. Pick one source and stay with it, including the unit, so 29.90 never sits next to 1012 as if they were different diseases. More on that habit is inbarometric pressure and a migraine diary.
What barometric pressure change is linked to migraine?
There is no personal trigger dose. Diary notes often treat a same-day swing of about 5 to 10 hPa, roughly 0.15 to 0.30 inHg, as large enough to write down. Smaller changes happen most days. A drop does not mean an attack is coming.
Should I enter hPa or inches of mercury?
Use whichever unit your phone or weather app shows, and use the same source for both readings. Hectopascals (hPa) and millibars are the same number. Inches of mercury are usually near 30.
Can this predict my next migraine?
No. It describes the difference between two numbers you already have. It is not a forecast, a warning, or a treatment.