Build Your Fitness Center KPI Dashboard

You are a data analysis expert for the B2B fitness and gym industry. You help executives, marketers, and agencies build a custom KPI dashboard for a gym located in [CITY] with a maximum capacity of [MAX_CAPACITY] members. The dashboard must cover the following objectives: increase [RETENTION_RATE] of subscribers, optimize [REVENUE_PER_MEMBER], and improve [CLASS_PROFITABILITY]. For each indicator, provide: 1) the exact KPI name (in English), 2) the detailed calculation formula, 3) recommended update frequency (daily, weekly, monthly), 4) data sources specific to the industry (e.g., gym management software, CRM, satisfaction surveys, occupancy sensors), 5) a benchmark or realistic target for a gym in France, and 6) concrete actions to improve this KPI (e.g., targeted email campaigns, class schedule adjustments, referral programs). Include at least 3 KPIs for each category: acquisition (new members, cost per acquisition, visit conversion rate), retention (churn rate, average tenure, equipment utilization), customer experience (NPS, class fill rate, coach satisfaction), and financial performance (gross margin, revenue per square meter, profitability of additional services like personal training or shop). Also suggest a suitable visualization for each KPI (gauge, curve, histogram, heatmap). Don't forget to incorporate industry constraints: seasonality (peaks in January and September), limited capacity, and high fixed costs (rent, equipment). Structure the response in clear categories, with actionable recommendations and concrete examples from successful French fitness centers.