Free · No login required
Rack Space Planner
Arrange rack equipment from bottom to top, check used and free U, and export a numbered front elevation plan.
01 / Plan your rack
U1 is at the bottom. Items are packed from bottom to top.
Capacity and item heights: 1–60 whole U. Up to 30 items. Add a named spacer to reserve ventilation or future space.
Inputs stay on this page and clear on refresh.
02 / Your result
Rack Space Planner
Rack capacity: 12 U
- Used space
- 6 U
- Free space
- 6 U
Schematic only; row heights are not to scale.
Mounting height: 533.4 mm
1 U = 1.75 inches = 44.45 mm. Used space is the sum of all item heights, including any spacers you add. Positions start at U1 at the bottom and follow list order upward. Free space = max(0, capacity − used); over capacity = max(0, used − capacity). Mounting height is capacity × 44.45 mm, not the external case height. This is a sequential space plan; it does not check equipment depth, weight, mounting hardware, cooling or cable clearance.
Methodology
How it works
1 U = 1.75 inches = 44.45 mm. Used space is the sum of all item heights, including any spacers you add. Positions start at U1 at the bottom and follow list order upward. Free space = max(0, capacity − used); over capacity = max(0, used − capacity). Mounting height is capacity × 44.45 mm, not the external case height. This is a sequential space plan; it does not check equipment depth, weight, mounting hardware, cooling or cable clearance.
Method and assumptions documented by Techrider.live
Updated September 16, 2026
Frequently asked questions
How do I reserve ventilation or expansion space?
Add an item named for the gap or blank panel and enter its height in whole U. Follow each manufacturer’s clearance and ventilation instructions; this tool does not prescribe a universal cooling gap. Reorder items with the arrows: moving earlier places an item lower in the rack.
What happens when equipment exceeds the rack capacity?
The preview keeps every item visible and marks items that extend beyond capacity. The export includes the excess U so you can revise the plan. A 12U rack containing 1U, 2U and 3U items has 6U free; its mounting height is 533.4 mm. Reduce the equipment or choose sufficient capacity before installation.
Can I use this as an installation drawing?
Use it as an advance planning list. Confirm rail depth, shelf or adapter space, front and rear connections, load limits, stability and airflow against the actual rack and equipment manuals. U ranges are inclusive. The diagram is schematic; it does not measure equipment or show an existing rack.