CloudCostCompareHow to read a cloud cost estimate without being misled
An estimate is a model, not a quote. It is only as good as its assumptions, and the assumptions are often not on the first screen. This guide is about reading any estimate, and ours in particular.
Start with the assumptions, not the total
Before you look at the total, find the inputs: how much data, how many users, how many hours, which region. A total built on an assumption that is off by ten times is wrong by ten times, however carefully it was added up. If you cannot find the assumptions, treat the number as a guess.
Questions to ask of any estimate
- Which pricing model? On-demand, committed or spot? See cloud pricing models explained.
- Which region? Prices differ by region.
- What is left out? Data transfer, support, tax, logs and backups are often missing.
- Is it a month or a year? A monthly figure quoted next to an annual one is a common slip.
- What currency, and which rate? Rupee and dollar figures differ by the exchange rate used.
- Are the services really equivalent? Two prices compare only if the services do the same job in comparable ways.
Reading our results table
In the estimator, each cloud gets a column or block with a total and the lines behind it.
- Each line has a formula. Open it to see the quantity and the working. If the quantity looks wrong, your input was probably wrong.
- Each line links to the vendor’s own price page. Check any line you doubt.
- Tiered lines cost less than quantity times the first-tier price, because volume steps lower the price. The line says so.
Not offered, can’t be sized, unavailable
Three statuses stand where a number is missing, and they mean different things.
- Not offered: the cloud has no equivalent service. The line says why. It is not zero.
- Can’t be sized: the service exists, but the vendor publishes too little to work out how much you would need from your inputs.
- Price unavailable: we could not fetch the price. The last good price is kept and flagged when there is one.
A cloud with any of these has an incomplete total. It is a partial figure. It ranks below complete totals and is never called the cheapest, because leaving out a service would otherwise make a cloud look cheaper than it is.
Sensitivity: change one input at a time
The most useful thing you can do with an estimate is move one input and watch the total. If doubling the traffic doubles the cost, traffic is the driver. If it barely moves, look elsewhere. The estimator updates as you type, and the link in the address bar holds every input, so you can share the exact case.
What an estimate cannot tell you
How your real usage will behave, what discounts you will negotiate, how much tax applies, or how many people you will need to run it. Use the estimate to find the large drivers and compare shapes, then check the bill after the first month with how to read a cloud bill.
The rules behind our figures are in how we calculate monthly cloud costs, and a planning routine is in planning a cloud budget.