diff --git a/src/presa_mano/api/work_plane_routes.py b/src/presa_mano/api/work_plane_routes.py
index 99f3382..edd0b1b 100644
--- a/src/presa_mano/api/work_plane_routes.py
+++ b/src/presa_mano/api/work_plane_routes.py
@@ -11,6 +11,7 @@ from fastapi import APIRouter, HTTPException
 from pydantic import BaseModel, Field
 
 from ..perception import filter_outliers, nuwa_to_cv_frame
+from ..perception.projection import K_from_intrinsics, project_camera_to_pixels
 
 log = logging.getLogger(__name__)
 from ..perception.work_plane import (
@@ -66,7 +67,16 @@ def fit(req: FitReq) -> dict[str, Any]:
         )
     pts_cv = nuwa_to_cv_frame(pc[:, :3])
     with sw.step("filter_outliers"):
-        pts_cv = filter_outliers(pts_cv, n_std=2.0)
+        # Inline filter_outliers to keep the inlier mask, so we can project
+        # the SAME points back to RGB pixels for the GUI overlay.
+        if len(pts_cv) < 10:
+            inlier_mask = np.ones(len(pts_cv), dtype=bool)
+        else:
+            xyz = pts_cv[:, :3]
+            c_ = xyz.mean(axis=0)
+            d_ = np.linalg.norm(xyz - c_, axis=1)
+            inlier_mask = d_ < (d_.mean() + 2.0 * d_.std())
+        pts_cv = pts_cv[inlier_mask]
     if len(pts_cv) < 10:
         raise HTTPException(
             status_code=422,
@@ -103,10 +113,31 @@ def fit(req: FitReq) -> dict[str, Any]:
         idx = np.random.choice(len(scene_cv), req.max_preview_points, replace=False)
         scene_cv = scene_cv[idx]
 
+    # Project the inliers used for the fit back to RGB pixels so the GUI can
+    # overlay them on the live image (verify visually which depth pixels were
+    # actually fed to fit_plane_svd). pc is in OpenCV camera frame already
+    # (per pointcloud_roi docstring); use Nuwa's RGB intrinsics.
+    fit_points_px: list[list[int]] = []
+    try:
+        intr_full = nuwa.intrinsics()
+        rgb_intr = intr_full.get("rgb")
+        if rgb_intr and rgb_intr.get("fx") and rgb_intr.get("cx"):
+            # Inject width/height so K_from_intrinsics has all required keys.
+            W = int(rgb_intr.get("width", 640))
+            H = int(rgb_intr.get("height", 480))
+            rgb_intr = {**rgb_intr, "width": W, "height": H}
+            K = K_from_intrinsics(rgb_intr)
+            inliers_cv = pc[inlier_mask, :3]   # original CV-frame coords
+            with sw.step("project_inliers"):
+                fit_points_px = project_camera_to_pixels(inliers_cv, K, (W, H)).tolist()
+    except Exception as e:
+        log.warning("could not project fit inliers to RGB pixels: %s", e)
+
     return {
         "plane": asdict(wp),
         "preview": True,
         "points_camera": scene_cv.tolist(),
+        "fit_points_px": fit_points_px,
         "timings_ms": sw.as_dict(),
     }
 
diff --git a/web/work_plane.js b/web/work_plane.js
index 3325b65..8a8b5ac 100644
--- a/web/work_plane.js
+++ b/web/work_plane.js
@@ -10,6 +10,7 @@ const RGB_REFRESH_MS = 1000;
 let roi = null;            // {u0,v0,u1,v1} in image pixel coords
 let previewPlane = null;   // last response.plane (preview, not saved)
 let previewPoints = null;  // list of [x,y,z] in CV camera frame, meters
+let fitPointsPx = null;    // list of [u,v] pixels of inliers used for the fit
 let savedPlane = null;     // last GET /api/work_plane response.plane
 
 function setChip(text, level) {
@@ -89,6 +90,12 @@ function startRgbLoop() {
   function drawOverlay() {
     const ctx = overlay.getContext('2d');
     ctx.clearRect(0, 0, overlay.width, overlay.height);
+    // Inliers used for the last fit, drawn first so the ROI rectangle stays
+    // on top.
+    if (fitPointsPx && fitPointsPx.length) {
+      ctx.fillStyle = '#4da3ff';
+      for (const [u, v] of fitPointsPx) ctx.fillRect(u, v, 2, 2);
+    }
     if (roi) {
       ctx.strokeStyle = '#9b6dff';
       ctx.lineWidth = 2;
@@ -99,11 +106,15 @@ function startRgbLoop() {
       drawCross(ctx, firstCorner.u, firstCorner.v);
     }
   }
+  // Re-export so doFit can refresh the overlay after a successful fit.
+  window.__wpDrawOverlay = drawOverlay;
 
   viewport.addEventListener('click', (e) => {
     const p = imgPixelFromEvent(e);
     if (firstCorner === null && roi === null) {
-      // First click: place corner A.
+      // First click: place corner A. Drop any stale fit-points overlay so we
+      // don't suggest the new ROI is being analyzed yet.
+      fitPointsPx = null;
       firstCorner = p;
       drawOverlay();
       setChip('punto 1/2 piazzato — clicca il secondo angolo');
@@ -132,6 +143,7 @@ function startRgbLoop() {
     }
     // ROI already set: start a new selection on the next click.
     roi = null;
+    fitPointsPx = null;
     firstCorner = p;
     drawOverlay();
     setRoiInfo();
@@ -277,8 +289,10 @@ async function doFit() {
     if (r.detail) throw new Error(formatDetail(r.detail));
     previewPlane = r.plane;
     previewPoints = r.points_camera;
+    fitPointsPx = r.fit_points_px || null;
     three.setPlane(previewPlane);
     three.setScatter(previewPoints, previewPlane, previewPlane.offset_mm);
+    if (window.__wpDrawOverlay) window.__wpDrawOverlay();
     renderDetails(previewPlane);
     $('wpStateBlock').innerHTML = `<strong>preview</strong> · RMS ${previewPlane.fit_rms_mm.toFixed(1)} mm · n_inliers ${previewPlane.n_inliers} · offset ${previewPlane.offset_mm} mm · <span class="warn">non salvato</span>`;
     setChip('preview pronto', 'ok');