Mandaluyong is 96% larger than San Juan, Metro Manila.
Area: 11 km2 calculated
Mandaluyong, officially the City of Mandaluyong, is one of the cities and municipalities that comprise Metro Manila in the Philippines. Wikipedia
Area: 6 km2 calculated
San Juan is a city in the Philippines. It is one of the cities that comprises Metro Manila, the National Capital Region of the Philippines. It is the smallest city in the country in terms of land area. Wikipedia