Cloud Cost Calculator
A monthly cloud bill from its parts — compute hours, storage, egress and requests — and what a one-year commitment saves against on-demand.
Cloud bills are four things: instance-hours, storage per GB-month, data leaving the provider, and per-request charges.
How the cloud cost calculator works
Cloud bills are four things: instance-hours, storage per GB-month, data leaving the provider, and per-request charges. Egress is the one that surprises people, because it is free coming in and expensive going out.
The commitment discount is the other lever. Reserving capacity for a year typically saves 30 to 40% against on-demand, but only on the baseline you actually run continuously — reserving a peak you hit twice a month costs more than it saves.
Formula: monthly = instances × hours × rate + storage + egress + requests
Worked examples
| Inputs | Monthly cost | Note |
|---|---|---|
| Six instances and 1.5 TB out | 1,029.2 | compute dominates |
| Heavy egress | 2,694.2 | transfer becomes the largest line |
| No commitment | 1,029.2 | no saving |
FAQFrequently asked questions
What drives a cloud bill?
Compute usually, then egress. Storage is cheap per gigabyte and rarely the problem unless you are keeping everything forever.
Why is data transfer out so expensive?
Because it is priced as a product, not a cost. Inbound is free; outbound is billed per gigabyte at rates far above what bandwidth costs.
Should I commit to a year?
On the baseline you genuinely run all the time, yes — 30 to 40% is a large discount. On anything bursty, no: you pay for the reservation whether you use it or not.
What is a GB-month?
One gigabyte stored for one month. Storage billed at 0.023 per GB-month costs 23 for a terabyte held all month.
How do I cut the bill?
Right-size instances first, then look at egress — a CDN in front of the origin often pays for itself immediately. Reserved capacity is third, not first.
Where these figures come from
- IEC 80000-13 — Information science and technology (quantities and units) — the decimal (kB, MB) versus binary (KiB, MiB) prefixes used throughout
- RFC 4632 — Classless Inter-domain Routing (CIDR) — the address-plan arithmetic behind the subnet calculator
- RFC 1918 — Address Allocation for Private Internets — the private ranges the subnet calculator recognises
- NIST SP 800-63B — Digital Identity Guidelines, Authentication — length over composition rules; the basis of the password guidance here
- NIST SP 800-57 Part 1 — Recommendation for Key Management — key-strength comparisons used by the key-space calculator
- National Cyber Security Centre — password guidance — UK national guidance on password policy
Last checked: September 2026. Units follow the SI decimal convention (IEC 80000-13 defines the binary alternatives); network and security figures cite the defining standard.