Best tip calculator for designers

There are roughly 200+ tip calculator apps in the app stores, but almost all are generic—built for restaurants, bars, and taxis with zero customization for freelance or design work. The common failure is one-size-fits-all inputs: they assume a bill total, a party size, and a percentage, then stop. Designers need something different: the ability to calculate tips on retainers, split invoices across multiple clients, track tips as tax-deductible income, or apply custom formulas (e.g., 15% for small projects, 10% for high-volume work). The actual gap isn't the calculation itself—it's the context layer. Most designers either skip tipping their collaborators entirely, use a notes app, or overpay out of guilt because they don't have a repeatable system. A shipper entering this space should focus on niche customization: build specifically for creatives (designers, developers, photographers) with templates for common scenarios, tax reporting integration, and team tip-splitting. The secondary play is making it social—let designers benchmark their tipping practices and build cultural momentum around fair compensation in creative work.