TV size starts with seat distance, not floor area
A large room can still put your seat close to a wall. Eye-to-screen distance determines how much of your view the image fills; total floor area does not.
Inches describe the diagonal
A 65-inch television is not 65 inches wide. Its 16:9 aspect ratio relates width to height. Leave room for the stand and frame using the actual model dimensions, not the image diagonal alone.
References: Samsung
Translate distance into viewing angle
Samsung discusses 30–40° as a viewing reference. Our geometry uses width = 2 × distance × tangent of half the angle, then derives the 16:9 diagonal. This is an explicit geometric model, not a medical rule or comfort guarantee.
Compare an experience, not one number
At 2.5 m, the model gives about 60.5 inches at 30° and 82.2 inches at 40°. The larger end fills more of your view; resolution, content and preference still matter.
A 65-inch 16:9 image is about 144 cm wide, but the television body can be wider. Measure the installation space and check the product dimensions.
Moving the seat 20% closer reduces the diagonal for the same viewing angle by 20%. Try the seating position before raising the budget; changing the room area is unnecessary.