Cloud vs On-Premise TCO Calculator

How the total cost is calculated

The calculator adds up, year by year, everything each option costs. All costs are in the currency you choose:

On-premise, year n  = hardware (in year 1 and every time its useful life ends)
                    + kW × 8,760 hours × price per kWh
                    + software licenses + space or data center
                    + IT hours per month × 12 × cost per hour

Cloud, year n       = monthly cloud cost × 12 × (1 + annual growth)^(n − 1)
                    + IT hours per month × 12 × cost per hour
                    + migration (year 1 only)

Each option’s cumulative cost is the sum of its years. The cheaper option in a given year is the one with the lower cumulative cost up to that year, and the costs cross whenever the cheaper option changes. A hardware renewal can make the costs cross more than once.

Worked example

A company runs its applications on its own servers. New hardware costs $60,000 and lasts 4 years. The servers draw 3 kW on average at $0.15 per kWh, the software licenses cost $8,000 a year and the server room $6,000 a year. The IT team spends 40 hours a month on them, at $60 an hour. In the cloud, the same workload would cost $3,500 a month in year 1, growing 15% a year, with a $15,000 migration and 15 hours a month of IT work.

• Electricity: 3 × 8,760 × $0.15 = $3,942 a year
• On-premise IT staff: 40 × 12 × $60 = $28,800 a year
• On-premise running costs: $3,942 + $8,000 + $6,000 + $28,800 = $46,742 a year, plus $60,000 of hardware in years 1 and 5
• Cloud, year 1: $42,000 + $15,000 of migration + $10,800 of IT staff = $67,800; by year 5, $84,258 a year

Costs cross more than once, in years 4 and 5. On-premise pulls ahead in year 4, once the hardware is paid off, but the renewal in year 5 hands the lead back to the cloud. Over 5 years, the cloud saves $1,530: practically a tie, so the decision depends on what happens after year 5 and on factors the calculator doesn’t measure.

Amounts are rounded exactly as the calculator shows them; each step uses the unrounded values.

How the hardware’s useful life changes the result

With the same costs, this is the 5-year total depending on how long the hardware lasts before it is renewed:

With a life of 3 or 4 years, the hardware is bought twice within 5 years and the cloud comes out slightly ahead. With 5 years or more, it is bought only once and on-premise saves $58,470. Look at the year after the horizon too: right after a renewal, on-premise starts a new cycle with its biggest expense already paid.

When each option tends to win

1. Stable, predictable workloads favor on-premise: you pay for capacity once and use it fully for years.
2. Variable or fast-growing workloads favor the cloud: you pay for what you use and avoid buying capacity in advance.
3. Small IT teams gain more from the cloud, because the provider takes over hardware, power and physical maintenance.
4. Strict data location or latency requirements can push towards your own servers or a hybrid setup.
5. Optimize the cloud before comparing. Reserved capacity, savings plans and turning off idle resources can lower the monthly bill considerably.

What this estimate doesn’t include

It doesn’t include the resale value of old hardware, financing costs, backup and disaster-recovery sites, downtime risk, or the cost of buying more servers if you outgrow the original ones. Nor does it include the flexibility of scaling up or down in the cloud. Use the result to compare scenarios and start the conversation, not as a final quote.