Data Transfer Cost Calculator
What a metered data plan or overage actually costs — included allowance, extra usage and the per-gigabyte rate turned into a real bill.
How it works
total = base price + max(0, used − included) × rate per GB
A metered bill has two parts: a flat base for the included allowance, and an overage charge for every gigabyte beyond it. The sting is the per-GB rate — often ten to fifty times the effective price of the bundled data — so a modest overrun can dwarf the base fee. Dividing the total by the data actually used gives the real cost per gigabyte, the honest number for comparing plans.
Worked example
A $60 plan includes 200 GB; you use 350 GB with a $0.10/GB overage. Overage is (350 − 200) × $0.10 = $15, so the bill is $60 + $15 = $75 — an effective $0.214 per GB, more than double the plan’s headline rate.
Frequently asked questions
How do I avoid overage charges?
Track usage mid-cycle, shift big downloads and backups to unmetered Wi-Fi, and cap streaming quality on the road. If you overshoot most months, a larger allowance is almost always cheaper than paying the per-GB rate.
Why is the effective per-GB cost higher than the overage rate?
Because the flat base fee is spread across every gigabyte, not just the overage. When you use little data the base dominates and the effective rate is high; heavy use spreads it thinner.
Is unlimited data always cheaper?
Only if you regularly hit overage. If your usage sits well under the allowance most months, a metered plan with a lower base can beat an unlimited one — this tool lets you compare both on effective cost per GB.
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This calculator is for educational purposes. Double-check important results before acting on them.