Why this exists
Most restaurants that publish nutrition information publish it as a PDF, or as a slow official app buried a few taps deep, or as a chart of whole pre-built menu items that doesn't tell you what happens when you swap the bread, skip the cheese, or add a second scoop of guac. If you actually wanted to know what your specific order costs — not the "regular" version, yours — you were stuck doing the arithmetic yourself from a PDF, or trusting a random blog's rough estimate.
Third-party "nutrition calculators" often make this worse: they average a handful of menu items into a single number, or extrapolate calories from a photo, or just guess. That's fine for a ballpark, but it isn't the same as knowing what's actually in your food.
The idea behind this site: when a restaurant publishes real per-ingredient nutrition data, there's no reason a calculator should still be guessing. Build the exact order, sum the exact ingredients, get the exact number.