How Much Data Does a Travel SIM Really Need?
Buying a local SIM card abroad is one of the smartest ways to cut roaming costs — but choosing the right data plan can be tricky. Buy too little and you end up throttled; buy too much and you waste money. This calculator helps you estimate the exact amount of data you'll need based on your trip length and daily usage habits, so you can pick the right plan before you leave home.
Daily usage estimates used here reflect real-world behavior: light users who mainly message and check maps use around 100 MB/day; average users who browse social media and occasionally watch short videos use roughly 300 MB/day; heavy users who stream video, make video calls, or upload content regularly can burn through 700 MB to 1.5 GB per day. These figures assume you're not connecting to Wi-Fi — if you use hotel or café Wi-Fi frequently, your actual SIM consumption will be much lower.
One important thing to know: most international travel SIMs don't charge extra once you hit your data cap — they throttle your speed instead (typically to 1 Mbps or less). Maps and messaging still work at throttled speeds, but streaming video becomes nearly impossible. Buying a slightly larger plan than you think you need is usually the safer bet.
Frequently Asked Questions
For trips longer than 3–4 days, a local SIM is almost always cheaper. US carriers typically charge $5–$15 per day for international data add-ons. A local SIM with 5–10 GB often costs $10–$25 total for the same trip.
Buying online before your trip is often cheaper and means you'll have a working number the moment you land. Airport SIM kiosks at your destination are convenient but usually 20–40% more expensive.
Yes — a travel SIM gives you a temporary local number. Use internet-based apps like WhatsApp, FaceTime, or Google Voice to stay reachable on your regular number while abroad.