Your assumptions (all adjustable)
5-year total cost of ownership
On-premise is cheaper by £99,523Cumulative cost over time
Where the money goes
Indicative model — every assumption above is adjustable; enter your own quotes for an accurate result. Excludes one-off migration effort, vendor discounts and reserved-instance / committed-use pricing.
The real comparison is total cost, not the sticker
“Cloud vs on-prem” is rarely won on the headline number. The decision turns on the costs that sit around the obvious one — and they fall on both sides. This calculator lays them out over a 3–10 year horizon and draws the break-even point, using your figures (every default is an adjustable, indicative starting point, not a quote).
The cost lines each model carries — the ones a sticker comparison misses.
What on-premise really costs
Beyond the hardware itself: power and cooling (UK business electricity is roughly £0.25–£0.35/kWh, and a server room’s PUE of ~1.4–1.8 means cooling adds 40–80% on top of the IT draw), a refresh cycle every ~5 years, maintenance and support, plus the staff time to run it. The calculator amortises capex across refresh cycles and runs power, maintenance and staff across the whole horizon.
What cloud really costs
Cloud removes the upfront capital and gives you elasticity — genuinely the right answer for spiky or uncertain workloads. But the running bill carries data egress, the annual price increases cloud services tend to apply, and the FinOps effort to stop sprawl. For a steady, 24/7 workload, those compound — which is why the break-even chart sometimes shows on-prem overtaking cloud, and why some organisations with stable heavy workloads have repatriated.
Use it to frame the decision, then get it costed
This tool is for an honest first-pass: change the assumptions, watch the break-even move, and see which model your workload favours. It excludes one-off migration effort and committed-use discounts on purpose — those belong in a real quote. If you’re weighing a virtualization change too, pair it with the VMware migration cost calculator.
💷 Want it costed for real? Servnet sizes both options against your actual workload — hardware, hosting, cloud commitments and the migration in between — with no vendor bias. Get a TCO review →
Cloud vs on-premise — common questions
What does a TCO calculator include that a price comparison doesn’t?
A sticker comparison looks at hardware vs the monthly cloud bill. Total cost of ownership adds everything around them: on the on-prem side, power and cooling, the hardware refresh cycle, maintenance/support and the staff time to run it; on the cloud side, data egress, the annual price rises cloud bills tend to see, and the FinOps effort to keep them under control. Those “hidden” lines often decide the answer.
What are realistic numbers for power and cooling?
UK business electricity is roughly £0.25–£0.35 per kWh, and a typical server room runs at a PUE (power-usage effectiveness) of about 1.4–1.8 — meaning every watt of IT load pulls another 0.4–0.8 W of cooling and overhead. The calculator multiplies your IT draw by the PUE and your tariff across the horizon; adjust both to your site.
Why does cloud sometimes lose over five years?
Cloud is opex with no upfront capital and near-infinite elasticity, which is ideal for spiky or uncertain workloads. But for steady, predictable workloads run 24/7, paying monthly forever — plus egress and annual increases — can overtake a one-off hardware purchase that’s amortised over a 5-year refresh. The break-even point on the chart shows when on-prem catches up.
Is this why some companies are “repatriating” from cloud?
Partly. A number of organisations with stable, heavy workloads have moved them back on-prem (or to colocation) after the cloud bill kept climbing. It’s workload-specific, not a universal trend — this calculator is meant to help you decide for *your* workload rather than follow a headline.
How accurate is the result?
It’s exact arithmetic on the assumptions you enter — and every assumption is adjustable. The defaults are clearly-labelled indicative figures, not quotes. It deliberately excludes one-off migration effort, vendor discounts and reserved-instance/committed-use pricing, which are best captured in a proper quote.
Should I include staff costs on both sides?
Yes — both models need people. On-prem needs hands for hardware, patching and the data room; cloud needs cloud-engineering and FinOps time. Including a fair figure on each side keeps the comparison honest; set them equal if you genuinely can’t separate them.