# Fortify is the opposite of a snapshot - it is re-evaluated live on every single incoming hit

Unlike a DoT's locked-in buff state, Fortify's damage-reduction effect is recalculated fresh for every hit you take, comparing your CURRENT Life to your CURRENT Fortify amount at the moment of that specific hit.

Diablo IV patch 3.2.1. Category: snapshotting. Evidence: Confirmed.

## Detail
Fortify grants 10% damage reduction, but only for the portion of an incoming hit that would otherwise drop your Life to at or below your current Fortify value - not for the whole hit, and not based on any past state. If your Life is already above your Fortify amount, the top portion of a big hit gets none of this reduction; only the portion that would push you into/through your Fortify band benefits.

## Why it works
This is a live, per-hit overflow calculation rather than a stored buff: the game checks your Life and Fortify values at the exact moment damage is being applied for every incoming hit, with no memory of past Fortify totals.

## Numbers
Worked community example: 1,000 Life, 500 Fortify, hit for 600 damage. You end at 410 Life. The first 500 points of the hit (dropping you from 1000 to 500) get NO reduction; the remaining 100 damage (which would push you below your 500 Fortify) gets the 10% reduction, becoming 90 - hence ending at 1000-500-90=410 rather than 1000-600=400.

## How to use it
Fortify protects you best when your current Life is close to or below your Fortify amount already (e.g. after taking some chip damage); topping off to full Life right after a big Fortify application can waste most of the mitigation on your next hit, since the top part of your Life bar sits above the Fortify band.