FallPredict

FallPredict answers one question every time you’re standing on a ledge: “Would I die if I jumped from here?” — without making you count blocks or do mental math.

What it does

• Every client tick it casts a ray straight down from your feet to the first solid block or fluid surface below.
• It converts that drop height into the exact vanilla fall damage you’d take and shows it in the top-left of your HUD: e.g. “Fall: 12b -> 4.5 hrt”.
• The readout is color-coded: yellow = survivable, orange = half your health or more, red “LETHAL” = the fall would kill you at your current health.
• Over a bottomless drop it reads “Fall: void -> LETHAL”.
• The badge only appears when there’s an actual drop below you (more than the vanilla 3-block safe height), so it stays out of your way on flat ground.

Controls

• J — toggle the readout on/off. An action-bar message confirms the state.

How it’s built

• Uses a downward RaycastContext (collider + fluid surface) from the player’s feet — landing in water reads as a safe, low number.
• Damage uses the real vanilla formula ceil(fallDistance - 3) in health points, so the prediction matches what the game would actually deal.
• Lethality compares predicted damage against your live health, not max health.

Notes

• Pure client-side — install on your client only. Works on any Fabric server, fully vanilla compatible.
• Shows the base vanilla fall damage; it does not subtract Feather Falling, so treat it as a worst-case estimate for enchanted boots.
• The badge respects F1 (hide HUD) and hides while a menu is open.
• No config files, no dependencies beyond Fabric API.

Compatibility

Minecraft 1.21.8, 1.21.9, 1.21.10, 1.21.11 — Fabric Loader 0.16+. One JAR covers all four. Drop into your mods/ folder alongside Fabric API.