Why every number has a tilde

A calorie count is an estimate in every app, including the expensive ones. The database entry was measured on a different chicken than yours, the portion is a guess, and the oil in the pan never gets logged by anybody.

Sigma writes the tilde on the number rather than pretending. It also rounds to the precision a number can actually carry: whole calories, grams to a tenth. A reading of 140.262 kcal is arithmetic, not knowledge.

Where a number comes from is shown on the row: USDA, a barcode lookup, a label you scanned, a guess from a description, or your own typing. If a source looks wrong, tap the entry and fix it. Your correction wins.