diff --git a/web/tenant/src/views/service/playground/calculateCost.ts b/web/tenant/src/views/service/playground/calculateCost.ts
new file mode 100644
index 0000000..be88c03
--- /dev/null
+++ b/web/tenant/src/views/service/playground/calculateCost.ts
@@ -0,0 +1,44 @@
+export interface ModelPricing {
+	input_price?: number | string | null
+	output_price?: number | string | null
+	per_request_price?: number | string | null
+	billing_mode?: string | null
+}
+
+export interface TokenUsage {
+	prompt_tokens?: number
+	completion_tokens?: number
+	total_tokens?: number
+}
+
+/**
+ * calculateCost 根据模型定价和 token usage 估算费用
+ * @returns 格式化的费用字符串，如 "$0.001234"；无法计算时返回 null
+ */
+export function calculateCost(
+	model: ModelPricing | undefined,
+	usage: TokenUsage | undefined,
+): string | null {
+	if (!model || !usage) return null
+
+	const promptTokens = usage.prompt_tokens ?? 0
+	const completionTokens = usage.completion_tokens ?? 0
+
+	// 按次计费
+	if (model.billing_mode === 'per_request' && model.per_request_price) {
+		const price = Number(model.per_request_price)
+		if (price > 0) return `$${price.toFixed(6)}`
+		return null
+	}
+
+	// Token 计费
+	const inputPrice = Number(model.input_price ?? 0)
+	const outputPrice = Number(model.output_price ?? 0)
+
+	if (inputPrice <= 0 && outputPrice <= 0) return null
+
+	const cost = (promptTokens * inputPrice + completionTokens * outputPrice) / 1_000_000
+	if (cost <= 0) return null
+
+	return `$${cost.toFixed(6)}`
+}