Methodology and sources

Every number on this site is either a published figure from the source named beside it, or arithmetic applied to such figures with the assumptions written here.

1. Data estimates

The estimate is: for each activity, hours per day × megabytes per hour, summed, plus a daily background allowance, then multiplied by trip days. 1 GB is counted as 1,000 MB, as carriers and eSIM providers count it. The low figure uses the lower published rate for each activity and the high figure the upper one.

Hours per day by answer

The "typical" profile used on country pages is navigation some, social media some, browsing some, and none of the rest. "Light" is navigation and browsing only. "Heavy" sets navigation, social media and browsing to lots and the other three to some. These are assumptions, chosen to bracket common travel habits; the calculator lets you set your own.

Rates used by the calculator

Units are per hour except the background line, which is per day.

Every published figure collected

The calculator's rates are chosen from this fuller list, which is also what the guides cite.

Known limits

• Zoom and Google Meet figures are recommended or maximum bandwidth, and Netflix figures are "up to" values. Real use is often lower, which is why the low end of each range exists.
• YouTube, Instagram, TikTok, WhatsApp and FaceTime publish no per-hour figures. Generic carrier figures stand in for them, and the page says so where it matters.
• The navigation and social-media figures come from Consumer Cellular, a US carrier that publishes them; Verizon, AT&T and T-Mobile do not publish a per-hour figure for those activities.

2. Plugs and voltage

The IEC retired its World Plugs guide (confirmed 2026-10-19 at iec.ch/world-plugs). Plug types, voltage and frequency come from WorldStandards.eu country pages and were cross-checked on 2026-10-19 against the 'Mains electricity by country' table; all 25 agreed on plug types and voltage. Where references list a secondary socket type (for example type C alongside A and B in the Dominican Republic), the page lists the primary types. The "US plug fits" rule is: the country's list includes type A or type B. The "voltage differs" rule is: the supply is outside 100–127 V. South Korea is shown at 220 V, its official standard, where one reference lists 230 V.

3. eSIM prices and ranking

Prices were read from each provider's own country page on 2026-10-19: Airalo, Holafly, Saily and Nomad. Up to four plans per provider per country were recorded. Where a provider shows one price for several durations (Saily's unlimited plans) the plan was not recorded, because the price could not be matched to a duration. Some Nomad prices were sale prices on the day. Holafly's 1-day plans are priced only in euros and were left out.

Fixed-data plans are ranked by price ÷ GB. Unlimited plans are ranked by price ÷ days. A plan "covers" a trip if it is unlimited or its GB is at least the rounded high estimate, and its validity is at least the trip length. Affiliate commission is not an input to any ranking; see the disclosure.

4. Country set

Country set: the most-visited overseas destinations for US residents per the NTTO-derived ranking (TripleTrad, 2026-10-14, built on NTTO SIAT 2025), with three small Caribbean/Central American entries swapped for Australia, Iceland and Israel so every country has eSIM price coverage. The order is a guide, not an official rank. Source: Where Americans Travel Abroad 2026: Top 30 Countries (TripleTrad, 2026-10-14), derived from NTTO SIAT 2025 Annual + APIS/I-92.

5. Corrections

None yet. Corrections reported through the contact page are listed here with the date.

Data version 2026-10-19.