Cost per GB is useful for ranking plans that already fit your trip, but misleading as the main decision rule. Calculate it as cost per GB = payable plan price ÷ gigabytes usable at full speed. A $20 plan with 20 GB ($1/GB) beats a $12 plan with 6 GB ($2/GB) on unit price, yet costs more if you only need 4 GB.
- Eliminate plans that miss your destination, dates or hotspot needs before ranking by cost per GB.
- An unlimited plan with 1 GB/day of full speed counts as 7 GB over a seven-day trip.
- A 30 GB plan is waste for a four-day trip that uses 2 GB.
The basic formula
Cost per GB is payable plan price divided by the number of gigabytes you can use at the promised speed. For example, a hypothetical $12 plan with 6 GB costs $2/GB. A $20 plan with 20 GB costs $1/GB, yet you spend more money overall. If you only need 4 GB, the cheaper total plan may be preferable.
Only compare eligible options
Before ranking by cost per GB, eliminate plans that do not cover the destination, expire too soon, block required tethering or use a network unsuitable for your route. A cheap rate on an unusable plan has no value.
Use the effective allowance
A promotional unlimited offer with 1 GB/day of high-speed data does not have infinite full-speed gigabytes. For a seven-day trip, its maximum high-speed allowance under that rule is 7 GB, with the rest potentially throttled. Confirm whether unused daily allotment rolls over before calculating.
Add the probability of waste
A 30 GB package is not a bargain if a four-day trip uses 2 GB. Compare the total amount at checkout and forecasted usage, not just the price normalized to a larger advertised bundle.
Compare transparently
Our calculator reports both total price and price per GB so the trade-off stays visible. Prices entered by a user are illustrative unless checked against a current official listing.
Questions travelers also ask
How do I calculate price per gigabyte for an eSIM plan?
Divide the final price you pay by the gigabytes you can use at full speed. A $12 plan with 6 GB works out at $2 per GB. For daily-capped plans, multiply the daily fast allowance by the days you will use it, and do not count throttled data as extra gigabytes.
Why can the lowest cost per GB be the wrong plan?
Because bigger bundles almost always have a lower unit price, so ranking by cost per GB pushes you toward data you will never use. Unused gigabytes have no value. Pick the cheapest total that covers your realistic usage plus a small buffer, then use cost per GB to separate similar plans.
Does unused daily data roll over on unlimited eSIMs?
Do not assume it does. On many daily-capped plans the high-speed allowance resets each day and unused data is lost, which limits how much fast data you can really use. Check the plan's fair-use terms for rollover before you calculate its effective allowance.
Sources
Disclosure: this site shares ownership with TripoSIM and may benefit when you buy there. We do not claim independent lab testing or that any offer is the cheapest on the market. Prices and terms change, so the checkout page is authoritative.
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