Cost per Gigabyte

Why It Matters

Two plans with the same headline price can differ by an order of magnitude once the rates apply, and which is cheaper depends entirely on your shape of usage. A site holding 200 GB of archives that almost nobody downloads wants cheap storage and barely cares about transfer. A site holding 2 GB that gets downloaded constantly wants the opposite, and is better off wherever transfer is included rather than metered. Work out both numbers before choosing: gigabytes stored, and gigabytes likely to go out in a busy month. Getting that comparison backwards is how people end up on a plan whose bandwidth limit they reach in week two.

How It Works

Usage meters run continuously and are totted up at the end of each billing period. Storage is normally sampled — hourly or daily readings averaged across the month — so deleting a large file on the 28th saves very little. Transfer accumulates as responses go out and resets when the period does, which is why one bad week can bill more than the preceding quarter; that is the mechanism behind an egress fee. Most providers apply tiered rates, where the first terabyte costs one figure and volume above it costs less, and most round each line up to some minimum granularity. Read a rate card for three things: what the included allowance is, what the unit rate above it is, and whether requests are billed separately from bytes — per-10,000-request charges are trivial individually and meaningful for a site made of many tiny files.

Real-World Example

Common Mistakes

• ✕Comparing providers on the storage rate alone — for most public sites transfer is the larger and far less predictable half of the bill
• ✕Reading a free allowance as a cap rather than a threshold — on metered plans the meter keeps running past it and simply starts charging
• ✕Forgetting per-request charges on sites built from hundreds of small assets — the bytes are negligible, the request count is not

Related Terms