Reading an eSIM price list: headline price, price per GB, and which one lies
Reading an eSIM Price List: Headline Price, Price Per GB, and Which One Lies
When you're shopping for an eSIM plan, the first number you see is almost never the number that matters. eSIM providers list two prices side by side: the headline cost and the per-gigabyte rate. They often tell radically different stories about which plan is actually cheap.
Understanding this gap—and knowing how to spot it—is the difference between a genuine bargain and a plan that looks good only because you're looking at the wrong metric.
The Headline Price Trap
The cheapest plans by upfront cost tend to be the smallest ones. A 100 MB allowance for $0.31 sounds unbeatable until you do the math. When you divide the total cost by the data allowance in gigabytes, that same plan costs $3.08 per GB—the framework vendors use to report the actual value you're getting.
Voyasim's 500 MB plan for Japan breaks this pattern partly. It costs more in headline price ($0.50 versus Horizon's $0.31), yet the per-gigabyte rate is $1.00—three times cheaper than Horizon's. The tiny plans extract a penalty: they're sold at a markup because the per-transaction overhead is fixed, and spreading it across 100 MB instead of 500 MB doubles your cost per unit of data.
ESIM.DOG pushes this further. Their 100 MB plan for 1 day in Japan costs $0.53 upfront, which calculates to $5.30 per gigabyte—the most expensive of the smallest-plan category—because one day is such a narrow window that the per-unit cost balloons.
How to Actually Compare Plans
Work out the per-gigabyte cost yourself. Convert the data allowance to gigabytes (divide megabytes by 1,000), then divide the headline price by that figure. If a plan lists both, use that number to cross-check—but don't assume it's correct; the math errors between headline and per-GB rates are common enough to warrant verification.
A real-world example: Airalo's Moshi Moshi plan for Japan offers 5 GB of data for 30 days at $11.00. Divide $11.00 by 5 GB and you get $2.20 per gigabyte. This is cheaper than every sub-dollar plan listed above it by headline price. You're paying a higher upfront cost, but you're paying less for each gigabyte of actual data—and you get a month to use it, not one or seven days.
Sort your catalogue both ways. When you arrange plans by headline price, you see small allowances. When you arrange the same plans by per-gigabyte cost, you see larger allowances. Vendors know this: they often default to headline-price sorting, which surfaces the eye-catching small numbers first.
Why the Cheapest Isn't the Best Value
The markup on tiny plans exists for practical reasons—transaction costs, infrastructure, and customer support don't scale down with 100 MB—but it works against you. A 100 MB plan is a trap if you're comparing it only to its headline price. You need 10 of them to match one 1 GB plan, which means 10 separate purchases, 10 separate activations, and 10 times the friction.
Larger plans amortise this overhead. A 5 GB plan spreads the fixed costs across more data, bringing the per-gigabyte price down sharply. This is why an $11.00 plan with 5 GB can undercut a $0.31 plan with 100 MB, even though the first looks three times more expensive at the headline level.
The research cited here was gathered on 2026-08-01. Prices change: confirm current rates with the vendor before you buy, and always calculate the per-gigabyte cost yourself rather than relying on the provider's figure alone. The math takes 10 seconds and it catches errors and deliberate misdirection.