diff --git a/src/lib/server/db/schema.ts b/src/lib/server/db/schema.ts
index 86e54ae..47a4198 100644
--- a/src/lib/server/db/schema.ts
+++ b/src/lib/server/db/schema.ts
@@ -893,6 +893,8 @@ export const companyAccounts = pgTable(
 		creditLimit: numeric('credit_limit', { precision: 15, scale: 2 }),
 		statementCloseDay: integer('statement_close_day'),
 		paymentDueDay: integer('payment_due_day'),
+		// FX conversion to company base currency (e.g. 34.5 for USD→THB)
+		fxRateToBase: numeric('fx_rate_to_base', { precision: 18, scale: 8 }).notNull().default('1'),
 		// Banking integration link
 		externalAccountId: uuid('external_account_id').references(() => externalAccounts.id, {
 			onDelete: 'set null'
diff --git a/src/routes/(app)/companies/[companyId]/+layout.server.ts b/src/routes/(app)/companies/[companyId]/+layout.server.ts
index a3da916..2c90fde 100644
--- a/src/routes/(app)/companies/[companyId]/+layout.server.ts
+++ b/src/routes/(app)/companies/[companyId]/+layout.server.ts
@@ -27,10 +27,10 @@ export const load: LayoutServerLoad = async ({ locals, params }) => {
 		error(403, 'Not a member of this company');
 	}
 
-	// Total budget = sum of all non-deleted account balances
+	// Total budget = sum of all non-deleted account balances, converted to base currency
 	const [balanceRow] = await db
 		.select({
-			total: sql<string>`coalesce(sum(${companyAccountTransactions.amount}), '0')::text`
+			total: sql<string>`coalesce(sum(${companyAccountTransactions.amount} * ${companyAccounts.fxRateToBase}), '0')::text`
 		})
 		.from(companyAccountTransactions)
 		.innerJoin(companyAccounts, eq(companyAccountTransactions.accountId, companyAccounts.id))
diff --git a/src/routes/(app)/companies/[companyId]/accounts/+page.server.ts b/src/routes/(app)/companies/[companyId]/accounts/+page.server.ts
index 2be3760..d0a162b 100644
--- a/src/routes/(app)/companies/[companyId]/accounts/+page.server.ts
+++ b/src/routes/(app)/companies/[companyId]/accounts/+page.server.ts
@@ -112,6 +112,7 @@ type AccountFields = {
 	creditLimit: string | null;
 	statementCloseDay: number | null;
 	paymentDueDay: number | null;
+	fxRateToBase: string;
 	externalAccountId: string | null;
 };
 
@@ -171,6 +172,7 @@ function extractAccountFields(fd: FormData):
 			creditLimit: parseDecimalOrNull(fd.get('creditLimit')),
 			statementCloseDay,
 			paymentDueDay,
+			fxRateToBase: parseDecimalOrNull(fd.get('fxRateToBase')) ?? '1',
 			externalAccountId: trimOrNull(fd.get('externalAccountId'))
 		}
 	};
@@ -304,6 +306,7 @@ export const actions: Actions = {
 					creditLimit: f.creditLimit,
 					statementCloseDay: f.statementCloseDay,
 					paymentDueDay: f.paymentDueDay,
+					fxRateToBase: f.fxRateToBase,
 					externalAccountId: f.externalAccountId
 				})
 				.returning({ id: companyAccounts.id });
@@ -383,6 +386,7 @@ export const actions: Actions = {
 				creditLimit: f.creditLimit,
 				statementCloseDay: f.statementCloseDay,
 				paymentDueDay: f.paymentDueDay,
+				fxRateToBase: f.fxRateToBase,
 				externalAccountId: f.externalAccountId,
 				updatedAt: new Date()
 			})
diff --git a/src/routes/(app)/companies/[companyId]/accounts/+page.svelte b/src/routes/(app)/companies/[companyId]/accounts/+page.svelte
index 51b413c..7b5c5ce 100644
--- a/src/routes/(app)/companies/[companyId]/accounts/+page.svelte
+++ b/src/routes/(app)/companies/[companyId]/accounts/+page.svelte
@@ -143,6 +143,7 @@
 		creditLimit?: string | null;
 		statementCloseDay?: number | null;
 		paymentDueDay?: number | null;
+		fxRateToBase?: string | null;
 		externalAccountId?: string | null;
 	} = {}
 )}
@@ -176,7 +177,20 @@
 				class={inputCls}
 			/>
 		</div>
-		<div></div>
+		<div>
+			<label for="{prefix}-fxRate" class={labelCls}>FX Rate to Base</label>
+			<input
+				id="{prefix}-fxRate"
+				name="fxRateToBase"
+				type="number"
+				step="0.0001"
+				min="0.0001"
+				value={prefill.fxRateToBase ?? '1'}
+				placeholder="1.0 for THB, 34.5 for USD→THB"
+				class={inputCls}
+			/>
+			<p class="mt-0.5 text-xs text-gray-400 dark:text-gray-500">1.0 if same as company currency</p>
+		</div>
 
 		{#if type === 'bank'}
 			<div>
@@ -891,6 +905,7 @@
 								creditLimit: acct.creditLimit,
 								statementCloseDay: acct.statementCloseDay,
 								paymentDueDay: acct.paymentDueDay,
+								fxRateToBase: acct.fxRateToBase,
 								externalAccountId: acct.externalAccountId
 							})}
 							<div class="mt-3 flex justify-end gap-2">