Altimeter settings

In plain English

Set your altimeter correctly for the altitude band you're in. Below 18,000 ft MSL, use the current setting of a station within 100 nautical miles. At and above 18,000 ft MSL (the flight levels), set the standard 29.92 inHg.

Key points

• Below FL180: nearest station's setting (within 100 NM along the route).
• At/above FL180: set 29.92 (standard).
• Update the setting as you fly into a new station's area.

Common pitfalls

• Forgetting to reset from 29.92 on descent — a high pressure means you're lower than indicated.
• "High to low, look out below."

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*