diff --git a/bincio/serve/routers/gear.py b/bincio/serve/routers/gear.py
index 339656d..946b731 100644
--- a/bincio/serve/routers/gear.py
+++ b/bincio/serve/routers/gear.py
@@ -58,6 +58,14 @@ async def gear_add(
     if gear_type not in _GEAR_TYPES:
         raise HTTPException(400, f"type must be one of: {', '.join(sorted(_GEAR_TYPES))}")
     strava_id = str(body.get("strava_id", "")).strip() or None
+    weight_g = body.get("weight_g")
+    if weight_g is not None:
+        try:
+            weight_g = int(weight_g)
+            if weight_g < 0:
+                raise ValueError
+        except (TypeError, ValueError):
+            raise HTTPException(400, "weight_g must be a non-negative integer (grams)")
 
     user_dir = deps._get_data_dir() / user.handle
     items = _load(user_dir)
@@ -75,6 +83,8 @@ async def gear_add(
     }
     if strava_id:
         item["strava_id"] = strava_id
+    if weight_g is not None:
+        item["weight_g"] = weight_g
 
     items.append(item)
     _save(user_dir, items)
@@ -110,6 +120,18 @@ async def gear_update(
         item["type"] = gear_type
     if "retired" in body:
         item["retired"] = bool(body["retired"])
+    if "weight_g" in body:
+        w = body["weight_g"]
+        if w is None:
+            item.pop("weight_g", None)
+        else:
+            try:
+                w = int(w)
+                if w < 0:
+                    raise ValueError
+            except (TypeError, ValueError):
+                raise HTTPException(400, "weight_g must be a non-negative integer (grams)")
+            item["weight_g"] = w
 
     items[idx] = item
     _save(user_dir, items)
diff --git a/site/src/components/AthleteDrawer.svelte b/site/src/components/AthleteDrawer.svelte
index 6225f7c..be42db3 100644
--- a/site/src/components/AthleteDrawer.svelte
+++ b/site/src/components/AthleteDrawer.svelte
@@ -13,6 +13,7 @@
 
   let maxHr: number | null = null;
   let ftpW: number | null = null;
+  let weightKg: number | null = null;
   let hrZones: [number, number][] = [];
   let powerZones: [number, number][] = [];
   let seasons: { name: string; start: string; end: string }[] = [];
@@ -24,8 +25,9 @@
       const res = await fetch(`${editUrl}/api/athlete`);
       if (!res.ok) throw new Error(await res.text());
       const d = await res.json();
-      maxHr      = d.max_hr    ?? null;
-      ftpW       = d.ftp_w     ?? null;
+      maxHr      = d.max_hr     ?? null;
+      ftpW       = d.ftp_w      ?? null;
+      weightKg   = d.weight_kg  ?? null;
       hrZones    = d.hr_zones    ? d.hr_zones.map((z: number[]) => [z[0], z[1]] as [number,number]) : [];
       powerZones = d.power_zones ? d.power_zones.map((z: number[]) => [z[0], z[1]] as [number,number]) : [];
       seasons    = d.seasons ?? [];
@@ -76,6 +78,7 @@
         body: JSON.stringify({
           max_hr:       maxHr,
           ftp_w:        ftpW,
+          weight_kg:    weightKg,
           hr_zones:     hrZones,
           power_zones:  powerZones,
           seasons,
@@ -144,6 +147,14 @@
             class="w-full bg-zinc-900 border border-zinc-700 rounded-md px-3 py-2 text-sm text-white focus:outline-none focus:border-blue-500"
           />
         </label>
+        <label class="block">
+          <span class="text-xs text-zinc-500 mb-1 block">Body weight (kg)</span>
+          <input
+            type="number" min="30" max="200" step="0.1"
+            bind:value={weightKg}
+            class="w-full bg-zinc-900 border border-zinc-700 rounded-md px-3 py-2 text-sm text-white focus:outline-none focus:border-blue-500"
+          />
+        </label>
       </div>
     </section>
 
diff --git a/site/src/components/AthleteView.svelte b/site/src/components/AthleteView.svelte
index 820fb25..6eb92c8 100644
--- a/site/src/components/AthleteView.svelte
+++ b/site/src/components/AthleteView.svelte
@@ -53,7 +53,7 @@
   // Gear tab state
   interface GearReplacement { id: string; date: string; note?: string }
   interface GearPart { id: string; name: string; threshold_km?: number; replacements: GearReplacement[] }
-  interface GearItem { id: string; name: string; type: string; retired: boolean; strava_id?: string; parts?: GearPart[] }
+  interface GearItem { id: string; name: string; type: string; retired: boolean; strava_id?: string; weight_g?: number; parts?: GearPart[] }
 
   let gearItems: GearItem[] = [];
   let gearLoading = false;
@@ -66,6 +66,7 @@
   let gearEditName = '';
   let gearEditType = 'bike';
   let gearEditRetired = false;
+  let gearEditWeightG: number | null = null;
   let gearSaving = false;
   let gearExpandedId: string | null = null;
 
@@ -161,7 +162,7 @@
   }
 
   function gearStartEdit(item: GearItem) {
-    gearEditId = item.id; gearEditName = item.name; gearEditType = item.type; gearEditRetired = item.retired;
+    gearEditId = item.id; gearEditName = item.name; gearEditType = item.type; gearEditRetired = item.retired; gearEditWeightG = item.weight_g ?? null;
   }
 
   async function gearSaveEdit() {
@@ -171,7 +172,7 @@
       const r = await fetch(`/api/gear/${gearEditId}`, {
         method: 'PATCH', credentials: 'include',
         headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ name: gearEditName.trim(), type: gearEditType, retired: gearEditRetired }),
+        body: JSON.stringify({ name: gearEditName.trim(), type: gearEditType, retired: gearEditRetired, weight_g: gearEditWeightG }),
       });
       const d = await r.json();
       if (r.ok) {
@@ -673,6 +674,14 @@
                     <input type="checkbox" bind:checked={gearEditRetired} class="accent-blue-500" />
                     Retired
                   </label>
+                  <label class="flex items-center gap-1.5 text-sm text-zinc-400">
+                    <input
+                      type="number" min="0" step="1" placeholder="weight (g)"
+                      bind:value={gearEditWeightG}
+                      class="w-28 bg-zinc-700 text-white text-sm px-2 py-1 rounded border border-zinc-600 focus:border-blue-500 outline-none"
+                    />
+                    <span class="text-xs">g</span>
+                  </label>
                   <button
                     on:click={gearSaveEdit}
                     disabled={gearSaving || !gearEditName.trim()}
@@ -703,6 +712,9 @@
                     {#if gearDistances[item.name] > 0}
                       <span class="text-xs text-zinc-400">{formatDistance(gearDistances[item.name])}</span>
                     {/if}
+                    {#if item.weight_g}
+                      <span class="text-xs text-zinc-500">{item.weight_g >= 1000 ? (item.weight_g / 1000).toFixed(2).replace(/\.?0+$/, '') + ' kg' : item.weight_g + ' g'}</span>
+                    {/if}
                     {#if item.retired}
                       <span class="text-xs text-zinc-600 border border-zinc-700 rounded px-1.5 py-0.5">Retired</span>
                     {/if}
@@ -910,8 +922,14 @@
             <span class="text-white font-medium">{athlete.ftp_w} W</span>
           </div>
         {/if}
-        {#if !athlete.max_hr && !athlete.ftp_w}
-          <p class="text-zinc-500 text-sm">Set <code>athlete.max_hr</code> and <code>athlete.ftp_w</code> in your config, or use Edit profile.</p>
+        {#if athlete.weight_kg}
+          <div class="flex justify-between text-sm">
+            <span class="text-zinc-400">Weight</span>
+            <span class="text-white font-medium">{athlete.weight_kg} kg</span>
+          </div>
+        {/if}
+        {#if !athlete.max_hr && !athlete.ftp_w && !athlete.weight_kg}
+          <p class="text-zinc-500 text-sm">No key numbers set yet. Use Edit profile to add Max HR, FTP, and body weight.</p>
         {/if}
       </div>
 
diff --git a/site/src/lib/types.ts b/site/src/lib/types.ts
index 091a021..b6ce085 100644
--- a/site/src/lib/types.ts
+++ b/site/src/lib/types.ts
@@ -44,6 +44,7 @@ export interface AthleteJson {
   best_climbs?: BestClimb[];
   max_hr?: number;
   ftp_w?: number;
+  weight_kg?: number;
   hr_zones?: [number, number][];
   power_zones?: [number, number][];
   seasons?: { name: string; start: string; end: string }[];