The two numbers
FTP — the value in your Settings → Sports Settings. This drives everything: workout targets, zones, intensity and load calculations.
eFTP — Intervals.icu's rolling *estimate* of your FTP, recalculated continuously from your best recent efforts. Shown in Analytics as a trend line next to FTP.
Think of eFTP as the radar and FTP as the setting. eFTP moves on its own as you get fitter (or ride less); FTP only changes when you change it — deliberately.
Why targets aren't based on eFTP directly
Stability. eFTP jumps around with your recent riding, and workout targets that drift day-to-day make training unsteerable — and your devices, which hold their own FTP setting, would permanently disagree. So LeCoach keeps a stable FTP and tells you when the evidence says it should change.
How FTP updates in practice
When Intervals.icu detects a genuinely new FTP level from your riding, LeCoach shows it as an achievement with an Apply button — one tap updates your FTP everywhere and offers to re-sync upcoming workouts. Full flow: FTP tests and how your FTP updates.
Why is my Garmin FTP different?
Garmin runs its own estimate, like eFTP but with different math. Treat your LeCoach/Intervals.icu FTP as the source of truth and set other platforms to match it — especially indoor apps whose ERG mode converts %FTP targets to watts.