diff --git a/app/admin/accounting/page.tsx b/app/admin/accounting/page.tsx
index 86caef4..659c5d1 100644
--- a/app/admin/accounting/page.tsx
+++ b/app/admin/accounting/page.tsx
@@ -10,7 +10,7 @@ import PersianDatePicker from '@/components/admin/PersianDatePicker';
 import { Purchase, PAYMENT_GATEWAYS } from '@/types/purchase';
 import { PackageName } from '@/types/package';
 import { Product } from '@/types/product';
-import { formatPrice, getPurchaseFinalPrice, parseStoreRate } from '@/lib/utils';
+import { formatPrice, getPurchaseFinalPrice, parseStoreRate, parseFee } from '@/lib/utils';
 import {
     MagnifyingGlassIcon,
     ArrowPathIcon,
@@ -29,7 +29,7 @@ interface StoreSummary {
     count: number;
     gross: number;
     rate: number;
-    commission: number;
+    fee: number;
     net: number;
 }
 
@@ -55,24 +55,42 @@ interface AccountingResult {
 const computeAccounting = (
     purchases: Purchase[],
     myketRate: number,
-    cafeRate: number
+    cafeRate: number,
+    transactionFee: number,
 ): AccountingResult => {
     const rows = new Map<number, ProductRow>();
     let totalCount = 0;
     let totalGross = 0;
     let totalCommission = 0;
 
-    const makeStore = (rate: number): StoreSummary => ({ count: 0, gross: 0, rate, commission: 0, net: 0 });
+    // درصد سهم توسعه‌دهنده به‌صورت کسر (0.85) و کارمزد تراکنش به ریال
+    const makeStore = (rate: number): StoreSummary => ({ count: 0, gross: 0, rate, fee: 0, net: 0 });
     const myket: StoreSummary = makeStore(myketRate);
     const cafe: StoreSummary = makeStore(cafeRate);
     const other: StoreSummary = makeStore(0);
 
-    const collect = (store: StoreSummary, price: number, rate: number) => {
-        const commission = (price * rate) / 100;
+    // سهم توسعه‌دهنده برای مایکت/کافه‌بازار:
+    //   (P / 1.1 - T) × R
+    // P = قیمت فروش (با احتساب ۱۰٪ مالیات بر ارزش افزوده)
+    // /1.1 = حذف ارزش افزوده، T = کارمزد تراکنش به ریال، R = درصد سهم
+    const developerShare = (price: number, rate: number, feePerTransaction: number) => {
+        const beforeVat = price / 1.1;
+        const afterVatAndFee = beforeVat - feePerTransaction;
+        if (afterVatAndFee <= 0) return 0;
+        return afterVatAndFee * (rate / 100);
+    };
+
+    const collect = (store: StoreSummary, price: number, rate: number, feePerTransaction: number) => {
+        let net: number;
+        if (rate > 0) {
+            net = developerShare(price, rate, feePerTransaction);
+        } else {
+            net = price; // سایر درگاه‌ها: بدون کارمزد فروشگاه
+        }
         store.count += 1;
         store.gross += price;
-        store.commission += commission;
-        store.net += price - commission;
+        store.fee += price - net;
+        store.net += net;
     };
 
     for (const purchase of purchases) {
@@ -81,22 +99,26 @@ const computeAccounting = (
 
         let store: StoreSummary;
         let rate: number;
+        let feePerTransaction: number;
         if (gateway === PAYMENT_GATEWAYS.cafe.code) {
             store = cafe;
             rate = cafeRate;
+            feePerTransaction = transactionFee;
         } else if (gateway === PAYMENT_GATEWAYS.myket.code) {
             store = myket;
             rate = myketRate;
+            feePerTransaction = transactionFee;
         } else {
             store = other;
             rate = 0;
+            feePerTransaction = 0;
         }
 
-        collect(store, price, rate);
+        collect(store, price, rate, feePerTransaction);
 
         totalCount += 1;
         totalGross += price;
-        totalCommission += (price * rate) / 100;
+        totalCommission += price - developerShare(price, rate, feePerTransaction);
 
         const productId = purchase.product_id ?? purchase.product?.id ?? -1;
         let row = rows.get(productId);
@@ -117,8 +139,8 @@ const computeAccounting = (
         }
         row.count += 1;
         row.gross += price;
-        row.commission += (price * rate) / 100;
-        row.net += price - (price * rate) / 100;
+        row.commission += price - developerShare(price, rate, feePerTransaction);
+        row.net += developerShare(price, rate, feePerTransaction);
     }
 
     return {
@@ -151,9 +173,11 @@ export default function AccountingPage() {
     // Status filter — both paid statuses selected by default
     const [statuses, setStatuses] = useState<number[]>([...PAID_STATUSES]);
 
-    // Store commission rates (editable percentages)
-    const [myketRate, setMyketRate] = useState<string>('15');
-    const [cafeRate, setCafeRate] = useState<string>('15');
+    // درصد سهم توسعه‌دهنده (R در فرمول) — مایکت و کافه‌بازار به‌طور پیش‌فرض ۸۵٪
+    const [myketRate, setMyketRate] = useState<string>('85');
+    const [cafeRate, setCafeRate] = useState<string>('85');
+    // کارمزد تراکنش به ریال (T در فرمول سهم توسعه‌دهنده)
+    const [transactionFee, setTransactionFee] = useState<string>('1200');
 
     const [allPurchases, setAllPurchases] = useState<Purchase[] | null>(null);
     const [result, setResult] = useState<AccountingResult | null>(null);
@@ -198,19 +222,27 @@ export default function AccountingPage() {
             // Fetch all purchases once, then filter/aggregate in-memory.
             const purchases = await purchasesApi.getAllPurchases({ per_page: 500 }, token);
             setAllPurchases(purchases);
-            setResult(computeAccounting(purchases, parseStoreRate(myketRate), parseStoreRate(cafeRate)));
+            setResult(
+                computeAccounting(
+                    purchases,
+                    parseStoreRate(myketRate),
+                    parseStoreRate(cafeRate),
+                    parseFee(transactionFee)
+                )
+            );
         } catch (err) {
             setError(err instanceof Error ? err.message : 'خطا در دریافت داده‌ها');
         } finally {
             setIsLoading(false);
         }
-    }, [token, myketRate, cafeRate]);
+    }, [token, myketRate, cafeRate, transactionFee]);
 
     // Recompute whenever filters or commission rates change (uses cached data)
     const runAnalysis = useCallback(() => {
         if (!allPurchases) return;
         const myket = parseStoreRate(myketRate);
         const cafe = parseStoreRate(cafeRate);
+        const fee = parseFee(transactionFee);
 
         const filtered = allPurchases.filter((p) => {
             // Status
@@ -233,8 +265,8 @@ export default function AccountingPage() {
             return true;
         });
 
-        setResult(computeAccounting(filtered, myket, cafe));
-    }, [allPurchases, statuses, selectedProductId, selectedPackageName, dateFrom, dateTo, myketRate, cafeRate]);
+        setResult(computeAccounting(filtered, myket, cafe, fee));
+    }, [allPurchases, statuses, selectedProductId, selectedPackageName, dateFrom, dateTo, myketRate, cafeRate, transactionFee]);
 
     // Recompute on filter/rate changes (no refetch needed once data is cached)
     useEffect(() => {
@@ -247,8 +279,9 @@ export default function AccountingPage() {
         setDateFrom('');
         setDateTo('');
         setStatuses([...PAID_STATUSES]);
-        setMyketRate('15');
-        setCafeRate('15');
+        setMyketRate('85');
+        setCafeRate('85');
+        setTransactionFee('1200');
     };
 
     const toggleStatus = (code: number) => {
@@ -368,11 +401,11 @@ export default function AccountingPage() {
                         </div>
                     </div>
 
-                    {/* Commission rates */}
+                    {/* Commission settings */}
                     <div className="mt-4 grid grid-cols-1 gap-4 sm:grid-cols-2 lg:grid-cols-3">
                         <div>
                             <label htmlFor="myket_rate" className={labelClass}>
-                                سهم مایکت (%)
+                                سهم توسعه‌دهنده مایکت (٪)
                             </label>
                             <input
                                 type="text"
@@ -381,12 +414,12 @@ export default function AccountingPage() {
                                 value={myketRate}
                                 onChange={(e) => setMyketRate(e.target.value)}
                                 className={inputClass}
-                                placeholder="۱۵"
+                                placeholder="۸۵"
                             />
                         </div>
                         <div>
                             <label htmlFor="cafe_rate" className={labelClass}>
-                                سهم کافه بازار (%)
+                                سهم توسعه‌دهنده کافه بازار (٪)
                             </label>
                             <input
                                 type="text"
@@ -395,12 +428,27 @@ export default function AccountingPage() {
                                 value={cafeRate}
                                 onChange={(e) => setCafeRate(e.target.value)}
                                 className={inputClass}
-                                placeholder="۱۵"
+                                placeholder="۸۵"
+                            />
+                        </div>
+                        <div>
+                            <label htmlFor="transaction_fee" className={labelClass}>
+                                کارمزد تراکنش (ریال)
+                            </label>
+                            <input
+                                type="text"
+                                id="transaction_fee"
+                                inputMode="numeric"
+                                value={transactionFee}
+                                onChange={(e) => setTransactionFee(e.target.value)}
+                                className={inputClass}
+                                placeholder="۱۲۰۰"
                             />
                         </div>
                     </div>
                     <p className="mt-2 text-xs text-gray-400 dark:text-gray-500">
-                        مایکت معمولاً ۱۵٪ یا ۳۰٪ و کافه بازار ۱۵٪ (زیر یک میلیارد تومان) یا ۳۰٪ کارمزد می‌گیرد.
+                        سهم توسعه‌دهنده = (قیمت ÷ ۱٫۱ − کارمزد تراکنش) × درصد سهم. پیش‌فرض مایکت و
+                        کافه‌بازار ۸۵٪ (فروش زیر ۱۰ میلیارد ریال) و ۷۰٪ (بالای آن) است.
                     </p>
 
                     <div className="flex items-center gap-3 mt-5">
@@ -566,7 +614,7 @@ function StoreCard({ title, summary }: { title: string; summary: StoreSummary })
                 <h4 className="text-sm font-semibold text-gray-900 dark:text-gray-100">{title}</h4>
                 {summary.rate > 0 && (
                     <span className="px-2 py-0.5 text-xs font-medium rounded-lg bg-indigo-50 text-indigo-700 dark:bg-indigo-500/15 dark:text-indigo-400">
-                        کارمزد {summary.rate}٪
+                        سهم توسعه‌دهنده {summary.rate}٪
                     </span>
                 )}
             </div>
@@ -580,8 +628,8 @@ function StoreCard({ title, summary }: { title: string; summary: StoreSummary })
                     <span className="text-gray-900 dark:text-gray-100 font-medium">{formatPrice(summary.gross)} تومان</span>
                 </div>
                 <div className="flex justify-between text-gray-500 dark:text-gray-400">
-                    <span>کارمزد</span>
-                    <span className="text-amber-600 dark:text-amber-400 font-medium">{formatPrice(summary.commission)} تومان</span>
+                    <span>سهم فروشگاه‌ها</span>
+                    <span className="text-amber-600 dark:text-amber-400 font-medium">{formatPrice(summary.fee)} تومان</span>
                 </div>
                 <div className="flex justify-between pt-1.5 border-t border-gray-100 dark:border-gray-800 text-gray-500 dark:text-gray-400">
                     <span>سود خالص</span>
diff --git a/lib/utils.ts b/lib/utils.ts
index 95d4c79..fdeb9d4 100644
--- a/lib/utils.ts
+++ b/lib/utils.ts
@@ -35,6 +35,16 @@ export const parseStoreRate = (value: string | number): number => {
     return Math.min(100, Math.max(0, n));
 };
 
+// Parse a non-negative integer input (e.g. transaction fee in Rial).
+export const parseFee = (value: string | number): number => {
+    if (value === null || value === undefined || value === '') return 0;
+    const str = String(value).replace(/[^\d]/g, '');
+    if (!str) return 0;
+    const n = parseInt(str, 10);
+    if (Number.isNaN(n)) return 0;
+    return Math.max(0, n);
+};
+
 export const formatDate = (dateString: string | null): string => {
     if (!dateString) return 'نامشخص';