Why you should not add room peaks to size an office

An office's busiest moment is not necessarily the sum of its rooms' busiest moments. Two rooms can each reach six people at different times. Adding those peaks gives twelve, even if the rooms never hold more than six people between them.

Density's Atlas reporting includes building and floor views, occupancy reporting and exports. Use the total for the boundary you are evaluating, with its reporting period and measure clearly defined. If you calculate a total from smaller spaces, align their observations before finding the peak.

Two rooms, the same averages, different peaks

Consider two separate rooms, A and B. The following readings are invented to explain the calculation. They are not Density measurements, customer results or a capacity recommendation.

Each table covers one hypothetical hour. Each row shows one 15-minute interval; assume the stated counts remain constant throughout that interval. Each person is in only one of the two rooms, and the combined boundary contains no other spaces.

In the first scenario, both rooms are busy together:

Interval starts	Room A	Room B	Combined count
09:00	6	6	12
09:15	6	6	12
09:30	0	0	0
09:45	0	0	0

Each room averages three people over the hour, reaches a peak of six and is occupied for half the hour. The combined count averages six and peaks at twelve.

In the second scenario, the rooms are busy at different times:

Interval starts	Room A	Room B	Combined count
09:00	6	0	6
09:15	6	0	6
09:30	0	6	6
09:45	0	6	6

Each room still averages three people, peaks at six and is occupied for half the hour. The combined average is still six. But the combined peak is now six, not twelve.

The room-level summaries are identical. The timing changes the answer.

Add simultaneous counts, then find the peak

Use counts that represent people on the same basis. A capped category such as three-plus is not an exact count. For separate spaces with compatible count measurements, add the counts at each common observation time. Then find the largest combined count in the period. Keep the original timestamps so someone else can reproduce the calculation.

Adding each room's independent maximum answers a different question: what if all rooms reached their recorded maximum together? The tables show why that number can exceed the peak that actually occurred.

Keep the measurement boundaries separate, too. Do not add a building's count to counts for rooms inside that same building. That would count some of the same people twice. Use the Entry doorway-counting guide when the question concerns a whole building or floor, and the Open Area guide when it concerns counts within an area.

Check what the exported interval means

Density's bulk CSV export documentation describes selectable time resolutions and average and peak occupancy for the selected period. It also identifies building and floor occupancy summary reports.

A room's peak within a 15-minute period does not tell you when inside that period the peak occurred. Adding two such peaks still does not establish that they happened together. Likewise, interval averages cannot reconstruct a brief peak hidden inside the interval. The constant counts in our invented tables make the example fully known; real interval summaries do not supply that assumption.

For a combined peak, use a report for the correct aggregate boundary or confirm that the available observations support a synchronized calculation. Check the time zone, missing-data treatment and measurement definitions before combining files. The building-comparison guide covers those reporting choices.

Use the result in a space decision

A simultaneous peak helps describe how many people occupied the measured spaces together. It does not establish everyone who wanted a space, whether groups could share rooms, or whether a smaller office would meet every operating requirement. Review room types, team needs and representative busy periods alongside the count.

For consolidation, carry that space evidence into the lease business case. The occupancy calculation and the timing of a lease change answer different parts of the decision.

Bring Density the boundary you want to evaluate and the report you are using. Book a demo, or email sales@density.io, to review the measurements and aggregation behind the result.

Browse occupancy guides and sensor comparisons · Read the plain-text version