Travel Data Planner

About

How much mobile data does your trip actually need? Travel Data Planner turns the way you use your phone into a number you can shop with — and then helps you get online abroad without overpaying. DATA CALCULATOR Pick a traveller profile or set your own hours per day for maps, social, browsing, music, video calls, streaming and laptop tethering. Set your trip length and get a GB estimate with a 30% safety buffer built in, plus the plan size to look for. BEFORE YOU FLY A seven-item checklist for the things that go wrong at the airport: carrier unlock, eSIM support, installing the eSIM on Wi-Fi, offline maps, roaming switched off, app data limits, and keeping calls on Wi-Fi. GET CONNECTED An honest side-by-side of travel eSIM, carrier day-passes, local SIM cards and pocket Wi-Fi — what each is good at and what it costs you. TRAVEL ASSISTANT (optional, bring your own API key) Ask follow-up questions about your specific trip. The assistant sees the estimate and checklist you just built, so its advice matches your plan. You supply your own API key for Anthropic, OpenAI, Google Gemini or any OpenAI-compatible endpoint; messages go straight from your phone to that provider. There is no subscription and no account. ENCRYPTED BACKUP Export everything to a passphrase-locked file using Argon2id and XChaCha20-Poly1305. The key is derived on your device and never leaves it — which also means a lost passphrase cannot be recovered by anyone, including us. BUILT TO STAY OUT OF THE WAY No account, no tracking, no ads. Everything except the optional assistant works fully offline. Light and dark themes, and English or Japanese. Data estimates are broad averages, not guarantees — actual use varies by app, quality settings and network. That is exactly why the calculator adds a buffer.