The Psychology of Pricing: Why 9.99 Works Better Than 10

The $9.99 Effect: How One Penny Tricks Your Brain Into Spending More Have you ever wondered why so many prices end in .99? Why not just round up to a clean number like $10? It's not coincidence—it's psychology. That single penny difference between $9.99 and $10.00 can increase sales by up to 24% according to MIT research. This is the power of charm pricing , one of retail's most effective psychological tricks. Let's break down why our brains perceive $9.99 as significantly cheaper than $10, even though the actual difference is negligible. The Left-Digit Effect: Why $9 ≠ $10 in Your Brain Our brains process numbers from left to right, placing disproportionate weight on the first digit we see. This left-digit effect causes $9.99 to register psychologically closer to $9 than $10, despi...