Cloud Carbon Footprint Calculator
Estimate the emissions of a cloud estate from vCPU hours, PUE and grid carbon intensity, and what a greener region saves.
Inputs
Power draw scales with load between an idle floor and a peak ceiling.
The Cloud Carbon Footprint model uses about 0.71 W idle for x86.
Roughly 1.2 W/TB for SSD and 0.65 W/TB for spinning disk.
Hyperscalers publish 1.1–1.6; on-premises rooms run 1.5–2.0.
About 400 g is the global average; coal-heavy grids exceed 700 g.
Nordic and hydro-backed regions sit under 50 g.
Monthly Carbon Footprint
585.0kg CO2e
Annual Footprint
7.02t CO2e
Monthly Electricity Drawn
1,330kWh
Footprint After Renewable Matching
585.0kg CO2e
Footprint in a Low-Carbon Region
65.8kg CO2e
Reduction from Moving Region
88.8%
Tree-Years to Absorb a Year of This
334tree-years
Step by step
Values used
Total vCPUs running = 800 vCPU; Average CPU utilisation = 40 %; Idle power per vCPU = 0.7100 W; Fully loaded power per vCPU = 3.50 W; Storage provisioned = 120 TB; Power per terabyte of storage = 1.20 W/TB; Hours in the month = 730 hours; Provider PUE = 1.14 ratio; Grid carbon intensity of your region = 400 gCO2e/kWh; Intensity of a low-carbon region = 45 gCO2e/kWh; Embodied carbon uplift = 10 %; Matched renewable energy = 0 %
Cloud Carbon Footprint
watts per vCPU = idle + (loaded − idle) × utilisation; kWh = (compute watts + storage watts) × hours ÷ 1000 × PUE; kgCO2e = kWh × grid intensity ÷ 1000 × (1 + embodied uplift).
Monthly Carbon Footprint
= 585.0 kg CO2e
Annual Footprint
= 7.02 t CO2e
Monthly Electricity Drawn
= 1,330 kWh
Footprint After Renewable Matching
= 585.0 kg CO2e
Footprint in a Low-Carbon Region
= 65.8 kg CO2e
Reduction from Moving Region
= 88.8
How it works
Server power is not proportional to load: a vCPU draws a substantial idle baseline and rises toward a loaded ceiling, so utilisation is interpolated between the two rather than multiplied. The resulting kilowatt-hours are scaled by PUE to account for cooling and distribution losses, then converted with the grid intensity of the specific region the workload runs in. Region choice usually dominates every other sustainability lever — the same workload can emit eight times more on a coal-heavy grid than on a hydro-backed one, and moving it costs nothing but latency. These are order-of-magnitude planning estimates; use your provider's own carbon reporting for anything you disclose.
Formula
Cloud Carbon Footprint
watts per vCPU = idle + (loaded − idle) × utilisation; kWh = (compute watts + storage watts) × hours ÷ 1000 × PUE; kgCO2e = kWh × grid intensity ÷ 1000 × (1 + embodied uplift).
- PUE
- Power usage effectiveness — facility power divided by IT power
- grid intensity
- Grams of CO2 equivalent emitted per kilowatt-hour on that grid
- embodied uplift
- Share added for manufacturing emissions amortised over hardware life
Frequently Asked Questions
How is Cloud Carbon Footprint calculated?
watts per vCPU = idle + (loaded − idle) × utilisation; kWh = (compute watts + storage watts) × hours ÷ 1000 × PUE; kgCO2e = kWh × grid intensity ÷ 1000 × (1 + embodied uplift). Server power is not proportional to load: a vCPU draws a substantial idle baseline and rises toward a loaded ceiling, so utilisation is interpolated between the two rather than multiplied. The resulting kilowatt-hours are scaled by PUE to account for cooling and distribution losses, then converted with the grid intensity of the specific region the workload runs in.
Why does Cloud Carbon Footprint matter?
Region choice usually dominates every other sustainability lever — the same workload can emit eight times more on a coal-heavy grid than on a hydro-backed one, and moving it costs nothing but latency. These are order-of-magnitude planning estimates; use your provider's own carbon reporting for anything you disclose.
What values do I need to enter?
This calculator takes 12 inputs: Total vCPUs running, Average CPU utilisation, Idle power per vCPU, Fully loaded power per vCPU, Storage provisioned, Power per terabyte of storage, Hours in the month, Provider PUE, Grid carbon intensity of your region, Intensity of a low-carbon region, Embodied carbon uplift, Matched renewable energy. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
Why does the answer differ from my provider's carbon dashboard?
Providers apply market-based accounting that nets off the renewable energy certificates they buy, and they use measured rather than modelled server power. This calculator is location-based and model-driven, which is the more conservative view and the one most useful for comparing regions.