We publish Dropkin, a water tracker built around the bottle you already carry. Save its capacity, then log a full bottle, half or quarter with a tap. Choose ounces or metric units, set reminder hours, and see your daily total against a personal goal. The free tracker includes unlimited logging, saved vessels, reminders, widgets and Apple Watch support; optional Pro adds styles and longer history. No account is needed, and logging works offline. Dropkin records a goal you choose; it does not determine your hydration needs or provide medical advice.