Short answer: the Big Mac Index is a single-product benchmark used to compare currency purchasing power. Burger Parity compares the USD cost of a selected multi-product basket with the mean across its covered countries. Their reference points and interpretations differ.
Primary methodological source: The Economist Big Mac data and methodology. Burger Parity is independent and is not affiliated with The Economist.
One product versus a basket
The Economist publishes raw and adjusted versions of its index along with underlying data. Its repository explains the sources and calculation changes. Burger Parity instead uses ten stored reference products and reports a relative basket-price score. Adding products does not automatically make an index more accurate; product selection, weighting and source quality determine what the number can explain.
How Burger Parity is calculated
For each country, multiply stored USD product prices by basket weights. Cap extreme prices at three times the median for that product. Normalize the covered weights if products are missing, with at least three weighted products required. Divide the country basket by the mean of valid country baskets and multiply by 100.
A score of 120 means that reference basket is 20% above the covered-country mean. It does not mean the currency is 20% overvalued or that a household needs 20% more income.
The expensive-device problem
Consider a hypothetical $1,000 device and a $5 meal, each with a 50% weight. Their contributions are $500 and $2.50. Equal weights still leave the device contributing over 99% of the combined value. Comparing normalized product-price ratios would answer a different question and should be published as a separate method, not silently substituted.
Data status: figures below come from the Burger Parity reference dataset. They are not independently verified current prices. An editorial revision is not a price verification date. Inspect the records and source labels.