Colocation Cost per kW Calculator

How the calculation works

The calculator reduces each quote to the same unit: dollars a month per kilowatt of power you can use. Cabinet prices, circuit prices and energy rates are hard to compare on their own, because the same price can buy very different amounts of usable power.

Usable power. Each circuit’s capacity comes from its voltage, breaker size and phase, using the same formulas as the amps to kW calculator:

• Single-phase: kVA = volts × amps ÷ 1,000
• Three-phase: kVA = √3 × volts × amps ÷ 1,000, with volts as the line-to-line voltage

Power is counted at a power factor of 1.0 (kW = kVA), the way circuit capacity is usually quoted. Two rules then reduce the breaker rating to what you can load:

• 80% rule: a circuit serving a continuous load is commonly limited to 80% of its breaker rating in North America, and colocation providers typically apply the same limit. Usable kW per circuit = kVA × 0.8.
• A+B redundancy: each circuit of an A+B pair is planned to at most 40% of its rating, so either feed can carry the whole load if the other fails. Usable kW = number of pairs × usable kW per circuit. Enter A+B power as pairs, the same way as the colocation power calculator: each pair is 2 billed circuits, one per feed.

These are planning rules, not electrical advice. Your provider’s contract states the limit it enforces.

Monthly cost in year 1. Space (cabinets × price per cabinet, or the cage price) + power + cross-connects (count × price) + remote hands (hours × rate) + setup charges ÷ term months.

• Breakered power: billed circuits × price per circuit, where billed circuits = 2 × pairs with A+B. You pay for the capacity whether or not you use it.
• Metered power: billed circuits × price per circuit (often lower, or 0) + energy, where energy = expected average kW × PUE multiplier × 730.5 hours × $ per kWh. 730.5 hours is an average month (365.25 days × 24 ÷ 12).
• Setup charges (non-recurring charges, or NRC) are spread evenly over the term, with no interest or discounting.

Three figures per kW, all divided by the same usable kW:

• Space and power per usable kW, year 1: (space + power) ÷ usable kW, closest to the per-kW price providers quote.
• All-in per usable kW, year 1: the whole year-1 monthly cost ÷ usable kW.
• All-in per usable kW, term average: total cost over the term ÷ term months ÷ usable kW. The cheapest quote is ranked on this figure.

Escalators. An annual escalator raises every recurring charge by the same percentage at the start of each contract year (months 13, 25 and so on), including metered energy, which keeps quotes comparable; real metered rates may follow the utility instead. Setup charges are paid once. Total over the term = setup + monthly recurring charges × the sum of (1 + escalator)^(contract year − 1) over every month of the term.

Cost per cabinet is the year-1 monthly cost ÷ the number of cabinets (for a cage, the cabinets it holds).

Worked example

Three quotes for four cabinets, all with A+B power at 208 V:

• Quote 1: 4 cabinets at $1,000; 4 A+B pairs of single-phase 30 A circuits (8 circuits) at $400 per circuit; 2 cross-connects at $300; $4,000 setup; 36 months; 3% escalator.
• Quote 2: 4 cabinets at $900; 4 A+B pairs of single-phase 20 A circuits (8 circuits) at $300 per circuit; 2 cross-connects at $300; $2,000 setup; 36 months; 3% escalator.
• Quote 3: 4 cabinets at $1,100; 2 A+B pairs of three-phase 30 A circuits (4 circuits) at $200 per circuit, metered at $0.12 per kWh with a 1.4 PUE multiplier and 12 kW expected draw; 2 cross-connects at $250; 2 hours of remote hands at $150; $2,500 setup; 60 months; 4% escalator.

Usable power:

• Quote 1: 208 × 30 ÷ 1,000 = 6.24 kVA per circuit; × 0.8 = 4.992 kW; × 4 pairs = 19.97 kW
• Quote 2: 208 × 20 ÷ 1,000 = 4.16 kVA; × 0.8 = 3.328 kW; × 4 pairs = 13.31 kW
• Quote 3: √3 × 208 × 30 ÷ 1,000 = 10.81 kVA; × 0.8 = 8.646 kW; × 2 pairs = 17.29 kW

Monthly cost in year 1:

• Quote 1: $4,000 space + $3,200 circuits (8 × $400) + $600 cross-connects + $4,000 ÷ 36 setup = $7,911.11
• Quote 2: $3,600 + $2,400 + $600 + $2,000 ÷ 36 = $6,655.56
• Quote 3: energy = 12 × 1.4 × 730.5 × $0.12 = $1,472.69; $4,400 + $800 circuits + $1,472.69 + $500 + $300 remote hands + $2,500 ÷ 60 = $7,514.35

Per usable kW, per cabinet and over the term:

• Quote 1: space and power $360.58, all-in $396.19 in year 1, $408.03 all-in averaged over the term; $1,977.78 per cabinet; $293,308 over 36 months
• Quote 2: space and power $450.72, all-in $499.97 in year 1, $514.99 averaged over the term; $1,663.89 per cabinet; $246,799 over 36 months
• Quote 3: space and power $385.87, all-in $434.54 in year 1, $470.52 averaged over the term; $1,878.59 per cabinet; $488,194 over 60 months

Quote 2 has the lowest monthly bill and the lowest cost per cabinet, but its 20 A circuits deliver a third less usable power, so it is the most expensive per kW. Quote 1 is cheapest per usable kW: $408.03 a month averaged over its term, 13.3% below Quote 3. Over 36 months at 3%, Quote 1’s recurring charges add up to 37.09 times the first month’s ($7,800 × 37.0908 + $4,000 setup = $293,308).

Reading the result

• Lowest per cabinet isn’t lowest per kW. Smaller circuits make a cabinet cheaper and the power dearer. If you will fill the cabinets with power-dense equipment, the per-kW figure is the one that matters.
• Redundancy halves usable capacity. An A+B quote and a single-feed quote with the same number of billed circuits are not the same offer: 4 A+B pairs and 8 single-feed circuits both bill 8 circuits, but the single-feed quote shows twice the usable kW and no protection against a feed failure. Compare like with like.
• Metered quotes depend on your draw. The calculator divides by the usable capacity of the circuits, so a metered quote looks better per kW as your expected draw falls and worse as it rises. Try your low and high estimates.
• Setup fees matter more on short terms. A $10,000 setup fee adds about $833 a month to a 12-month term and about $278 a month to a 36-month term.
• Escalators compound. At 4% a year, the fifth year of a contract costs about 17% more each month than the first.