The Mac Index indexes Apple website to get latest price of all Apple products, and display them in latest currency rates, after calculating any applicable tax rates, and tax refund rates.
It took metadata from Apple called Structured Data (which Google use for its Shopping site) on each product page, parse the price in each currency, and depending on the country, deduct or add the tax on the price, and display the final price. This ensures it only displays authoritative retail price from Apple, and not resellers or online shopping sites where prices are subject to occasional promotions and targeting.
The name took inspiration from The Big Mac Index, by The Economist. It has no similarities in term of economic concept.
For countries like United States, Canada, and Japan, the prices are displayed without sales tax. In USA and Canada, sales tax vary depending on state where you buy them, which is between 0.0% to 10.5%. In Japan, sales tax is 10.0% flat anywhere as of 2019, and it will simply be zero-rated once you provide your passport during your purchase.
For Hong Kong, Malaysia, Philippines, what is displayed is what you will pay. Apple did not state any applicable taxes, or there is any available tax refund programs.
For the rest, the prices are inclusive of VAT, GST, or similar-named taxes. Tax refunds are available depending on where you buy and and your nationality.
If you are traveling to certain country where the prices are lower after tax refunds, you definitely should take advantage of this loophole. These taxes are targeted and levied at citizen of that country alone. Neither Apple nor its resellers bear these additional cost you paid to them.
If you are traveling from countries with higher prices than usual, you also should take advantage of this information. Countries like Turkey, Brazil, and even Philippines has noticeably higher price than the rest of countries under Apple market. Plan your travel to include time to process the tax refunds.
If you are from country without official Apple presence, not always, but best believe that prices are usually higher due to reseller premiums.
If you simply want to go to a country specifically to buy Apple products, then it is not worth it for the effort and travel costs needed.
Thank you to my friend Shivon Ng for the tax refund loophole that inspired this latest iteration of The Mac Index. Thank you to Gaddafi Rusli for feedbacks and helps during its development.