diff --git a/pitch-deck/components/slides/FinanzplanSlide.tsx b/pitch-deck/components/slides/FinanzplanSlide.tsx
index 69d8268..5ca0904 100644
--- a/pitch-deck/components/slides/FinanzplanSlide.tsx
+++ b/pitch-deck/components/slides/FinanzplanSlide.tsx
@@ -62,6 +62,7 @@ const FORMULA_TOOLTIPS: Record<string, string> = {
   'Serverkosten Cloud (F)': 'Bestandskunden × 100 EUR + 500 EUR Basis',
   'Berufsgenossenschaft (F)': '2,77% der Brutto-Lohnsumme (VBG IT)',
   'Allgemeine Marketingkosten (F)': '10% vom Monatsumsatz',
+  'Gewerbesteuer (F)': '12,25% vom Gewinn (Messzahl 3,5% × Hebesatz 350%, nur bei Gewinn)',
   'Personalkosten': 'Summe aus Tab Personalkosten',
   'Abschreibungen': 'Summe AfA aus Tab Investitionen',
 }
diff --git a/pitch-deck/lib/finanzplan/engine.ts b/pitch-deck/lib/finanzplan/engine.ts
index 4fd6925..ae2c216 100644
--- a/pitch-deck/lib/finanzplan/engine.ts
+++ b/pitch-deck/lib/finanzplan/engine.ts
@@ -304,6 +304,29 @@ export async function computeFinanzplan(pool: Pool, scenarioId: string): Promise
     abrBetrieb.values = totalAfa
   }
 
+  // Gewerbesteuer (F): 12.25% of monthly profit (only when positive)
+  // Monthly profit = Revenue - Material - Personnel - AfA - other opex (excl. taxes)
+  const gewStRow = betrieb.find(r => r.row_label.includes('Gewerbesteuer'))
+  if (gewStRow) {
+    const nonTaxOpex = betrieb.filter(r =>
+      r.category !== 'steuern' && r.category !== 'personal' && r.category !== 'abschreibungen' &&
+      !r.is_sum_row && !r.row_label.includes('Summe') && !r.row_label.includes('SUMME')
+    )
+    const computed = emptyMonthly()
+    for (let m = 1; m <= MONTHS; m++) {
+      const rev = totalRevenue[`m${m}`] || 0
+      const mat = totalMaterial[`m${m}`] || 0
+      const pers = totalPersonal[`m${m}`] || 0
+      const afa = totalAfa[`m${m}`] || 0
+      let opex = 0
+      for (const r of nonTaxOpex) { opex += r.values[`m${m}`] || 0 }
+      const profit = rev - mat - pers - afa - opex
+      computed[`m${m}`] = profit > 0 ? Math.round(profit * 0.1225) : 0
+    }
+    await pool.query('UPDATE fp_betriebliche_aufwendungen SET values = $1 WHERE id = $2', [JSON.stringify(computed), gewStRow.id])
+    gewStRow.values = computed
+  }
+
   // Compute category sums
   const categories = ['steuern', 'versicherungen', 'besondere', 'marketing', 'sonstige']
   for (const cat of categories) {