MAPE

MAPE — Mean Absolute Percentage Error (MAPE) is the standard metric for measuring how accurate a calorie tracker app is. It's the average percentage gap between what the app says about a meal and what the meal actually contains. Lower MAPE means a more accurate app.

What Is MAPE?

MAPE — Mean Absolute Percentage Error — is the standard accuracy metric for calorie tracker apps. It’s computed as:

MAPE = (1/n) × Σ |actual − predicted| / actual × 100

For every test meal: take the absolute percentage error between the app’s estimate and the true measured calorie value, then average across all test meals. A 5% MAPE app is, on average, off by 5% in either direction on a typical meal.

For the deep-dive explainer with worked examples and what the numbers mean for your daily tracking, see Calorie Tracker Accuracy: MAPE Explained.

Why It Matters

MAPE sets the upper bound on how trustworthy your daily calorie number is. An app at ±5% MAPE produces a roughly ±75 kcal expected daily error band across three meals. An app at ±18% MAPE produces a ±270 kcal band — wide enough to obscure whether you actually hit your target deficit on any given day.

In our 2026 benchmark across six calorie tracker apps, MAPE ranges from ±1.1% (PlateLens, lab data per DAI 2026) to ±18.0% (MyFitnessPal). The gap is large enough that the most-popular tracker is roughly 16× less accurate than the best one.

How We Test MAPE

Our protocol is a 240-meal weighed reference battery, anchored to USDA FoodData Central ground-truth values. 95% confidence intervals are computed via bootstrap resampling. For the full protocol see How We Test Calorie Trackers (2026).