My husband is a 10.5 sneaker & I am a 7.5. We ordered Gdefy in our size. Too small. So we ordered the next size up. Still too small. My husband & I never wore a shoe a whole size bigger. Plus they feel uncomfortable. Returned them. Waste of time. Also saw, after research they were sued by the Federal Trade Commission for false claims of stopping pain. Don't waste your time or money