UPS Sizing Calculator

electrical

Sizes UPS systems for datacenter and critical power installations. Determines unit count from redundancy scheme (N, N+1, 2N, 2N+1), selects the next available rating from the ups-sizing-data table, and calculates efficiency losses, heat dissipation, cooling load, and battery runtime.

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It Load Kw*

Total IT or critical load in kilowatts that the UPS must support. Measure at the PDU output or sum all rack-level loads. Typical: 20-100 kW for server rooms, 100-1000 kW per UPS module in datacenters.

Power Factor

UPS output power factor used to convert kW to kVA for unit selection. Modern UPS systems are rated at 0.9 or 1.0 PF; legacy units at 0.8. Modern IT loads: 0.90-0.99. Legacy servers: 0.70-0.85. If omitted, defaults to 0.9.

Topology

UPS topology. 'online_double_conversion' = highest protection, zero transfer time, most common for datacenters; 'line_interactive' = lower cost, 2-4 ms transfer; 'rotary' = flywheel-based, large installations. If omitted, defaults to 'online_double_conversion'.

Redundancy

UPS redundancy scheme. N = no redundancy; N+1 = one spare module (concurrent maintenance); 2N = fully independent paths (fault tolerant); 2N+1 = 2N plus a spare. If omitted, defaults to 'N+1'.

Growth Margin Pct

Percentage added to IT load to account for future growth. Typical: 15-30% for new datacenters. Applied before UPS unit selection. If omitted, defaults to 20%.

Required Runtime Min

Minimum required battery runtime in minutes at full load. Typical: 5-10 min for generator-backed sites, 15-30 min without generators. If omitted, defaults to 10 minutes.

Modules Per Frame

Number of UPS modules per frame for modular UPS architectures. When set, total unit count is rounded up to fill complete frames. If omitted, no frame rounding is applied.

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Reference data

This calculator pulls live values from the following engineering reference tables in the database.

ups sizing data

About this calculator

UPS Sizing Calculator is part of the Engineering Database calculator suite. Each tool runs deterministic calculations against authoritative reference data and code-compliant methods, so results are reproducible and traceable to source standards.

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Reference data

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