Technology Tools
Buying decisions for cloud infrastructure and business software are usually made with a spreadsheet nobody trusts. These models make the inputs explicit — what is being counted, over what period, and what is deliberately excluded — so the output can be checked rather than taken on faith. Every assumption is listed on the page.
All technology tools
How these are grouped
- Cloud
- Infrastructure running costs and comparisons.
- SaaS
- Subscription software return and payback periods.
- Enterprise
- Total cost of ownership for larger systems.
Choosing the right tool
The Cloud Cost Calculator answers "what will running this infrastructure cost per month" — compute, storage and data transfer. The SaaS ROI Calculator answers a different question: whether a specific software purchase pays for itself, given what it saves against what it costs, including the one-off implementation year. The Software TCO Calculator is for comparing two options against each other over a multi-year period — use it for a build-vs-buy or vendor-A-vs-vendor-B decision, not for estimating one system's running cost.
Common mistakes
- Forgetting data egress when estimating cloud spend — providers generally charge for data leaving their network but not for data arriving, which is exactly why it's easy to leave out of a quick estimate and expensive to discover later.
- Quoting a SaaS business case on its steady-state ROI rather than year-one ROI, which hides the one-off implementation and training cost that actually determines whether the case pays back quickly.
- Leaving internal staff time out of a TCO comparison because no invoice arrives for it — it's usually the largest uncounted cost in a build-vs-buy decision.
- Choosing a TCO comparison period that happens to favour a preferred option, rather than the period the system will genuinely be used for — the worked example in the TCO guide below shows the cheaper option can flip depending on the period chosen.
A short example
A team is deciding whether to buy a £24,000/year SaaS tool with a £15,000 implementation cost, expecting to save 30 hours a week across 10 people.
Year-one cost is £39,000 against a benefit of roughly £59,000 at a £38 loaded hourly rate — a positive but modest first-year return, with a much stronger return from year two once the implementation cost drops out. Judging the case on the year-two figure alone, which is what a vendor is likely to quote, skips the year that actually has to be paid for first.
Technology guides
- How to Calculate the Real Cost of a SaaS SubscriptionThe number on the invoice and the number that determines whether the software was worth buying are usually different.
- Cloud Costs vs Total Cost of Ownership: What Each Model MissesA monthly cloud estimate and a five-year build-vs-buy comparison are answering two different questions — mixing them up produces the wrong one.
Frequently asked questions
- Are the cloud pricing figures live rates from AWS, Azure or Google Cloud?
- No — they're illustrative planning rates derived from published list pricing across major providers, clearly labelled as such on the tool. Use the output for the shape of a bill and for relative comparisons, then confirm the actual number against your chosen provider's own calculator before committing budget.