Why this exists
Every server vendor publishes a sizing tool. Dell has the Enterprise Infrastructure Planning Tool, HPE has the Power Advisor, Lenovo has the Power Configurator. They are all fine. They also all share the same three problems:
- They only know their own catalogue. Comparing a PowerEdge R760 against a ProLiant DL380 Gen11 means running two tools that make different assumptions and then squinting at two numbers that were never meant to be compared.
- They hide the formula. You enter a configuration, get a wattage, and have no way to see whether it assumed idle, typical, or flat-out, or what it did about power supply efficiency.
- They are sales funnels. Registration walls, quote requests, and "contact your account team" between you and a number you needed five minutes ago.
ServerCalc fixes all three. Every calculator shows its formula. Every page is free, signup-free, and built to give you a defensible number fast.
How the math is sourced
Each calculator's formula comes from publicly documented specifications and measurements:
- Chassis data: vendor technical guides and QuickSpecs for socket counts, DIMM slots, drive bays, and the power supply options actually offered on each platform.
- Component power: manufacturer-published TDP for every CPU and GPU, plus per-DIMM and per-drive figures from enterprise datasheets.
- PSU efficiency: the 80 PLUS internal-redundant efficiency targets at 230 V, interpolated across the load curve rather than flattened to the single headline percentage.
- Idle and load behavior: calibrated against published SPECpower_ssj2008 results. The reference case, a 2-socket ProLiant DL380 Gen11, lands within 2% of its measured idle figure.
- Facility math: standard conversions — 3.412 BTU/hr per watt, 12,000 BTU/hr per ton of refrigeration, the 80% continuous-load derate for circuit sizing, and PUE as published by the Uptime Institute's annual survey.
- Carbon intensity: national and regional grid factors from the Ember Global Electricity Review and IEA electricity reporting.
Where a vendor does not publish an exact number, we use conservative middle-of-the-road values that match real-world deployments, and we say so. See each calculator's "The formula" section for the specific derivation.
What's here today
9 calculators covering server power and energy, with cooling, capacity, virtualization, network, and cost calculators being added as the research surfaces underserved questions. The full list is on the homepage.
What's NOT here
- No accounts. There is nothing to sign up for.
- No tracking until you accept the cookie banner. See Privacy Policy.
- No paid placement. Calculators aren't ranked by who pays.
- No vendor sponsorship. If you see ads in the future, they'll be clearly labeled.
How this site stays free
The site is static-hosted and may eventually display ads to cover the domain renewal. The calculator math itself will always be free with no signup.
Contributing / corrections
If you find a bug, a wrong vendor spec, a server model you'd like added, or a measurement that disagrees with the estimate:
- Use the feedback form at the bottom of any calculator page. It goes straight to the inbox.
- Measured power figures are especially welcome. A BMC reading with the configuration next to it is worth more than any datasheet.
Bug reports about wrong math are the highest priority, accuracy is the whole point.
Legal
- Privacy Policy
- Cookie Policy
- Terms of Service
- Disclaimer, the most important one. Read it before relying on any number for electrical or cooling work.