That’s the idea! Definition 1 of 2Pro Tip 1/3Positive Reinforcement Use 'that's the idea!' to encourage someone when they're on the right track. You're folding the napkins correctly, that's the idea! Pro Tip 2/3Informal Affirmation 'That's the idea!' is informal; use it in casual conversations, not in formal settings. Fill the form out like this? - That's the idea! Pro Tip 3/3Light-Hearted Tone The phrase often carries a friendly, light-hearted tone, making the conversation more pleasant. Ah, you want me to help you cook? That's the idea!