Template · Architecture
Space program calculator (net to gross)
Converts a space program into net, department gross and building gross areas, with summary percentages.
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XLSXCSVODSXMLNumbers| Space program: spaces by department | |||||
| Example data — replace the blue input cells with your own. | |||||
| Department | Space | Quantity | Net area per space (m²) | Total net area (m²) | Notes |
| Public | Entrance lobby | 1 | 54.0 | 54.0 | |
| Public | Reception and waiting | 1 | 30.0 | 30.0 | |
| Public | Public WC, accessible | 2 | 4.5 | 9.0 | |
| Public | Multipurpose hall | 1 | 160.0 | 160.0 | |
| Public | Café servery | 1 | 17.5 | 17.5 | |
| Public | Library reading area | 1 | 133.0 | 133.0 | |
| Teaching | Classroom | 4 | 59.5 | 238.0 | |
| Teaching | Workshop | 1 | 96.0 | 96.0 | |
| Teaching | Seminar room | 1 | 30.0 | 30.0 | |
| Teaching | Teaching store | 2 | 10.0 | 20.0 | |
| Offices | Office, single | 2 | 14.0 | 28.0 | |
| Offices | Open-plan workstations | 1 | 70.0 | 70.0 |
Showing the first 16 of 26 rows and 6 of 6 columns. Cells with formulas show the formula on hover.
| Department and building grossing | ||||
| Example data — replace the blue input cells with your own. Change the blue factors to match your planning standard. | ||||
| Department grossing (circulation, walls and services inside each department) | ||||
| Department | Net area (m²) | Department grossing factor | Department gross area (m²) | Share of net area |
| Public | 403.5 | 18% | 476.1 | 36.8% |
| Teaching | 384.0 | 15% | 441.6 | 35.0% |
| Offices | 128.0 | 16% | 148.5 | 11.7% |
| Support | 79.5 | 12% | 89.0 | 7.2% |
| Services | 102.5 | 6% | 108.7 | 9.3% |
| Total | 1,097.5 | 15.2% | 1,263.9 | 100.0% |
| Total grossing factor in C11 is the weighted average of the department factors. | ||||
| Building grossing (shared lobbies, lifts, stairs, shafts, plant and external walls) | ||||
| Department gross area, total (m²) | 1,263.9 | |||
| Building grossing factor | 18% | Applied to the department gross area |
Showing the first 16 of 22 rows and 5 of 5 columns. Cells with formulas show the formula on hover.
| Space program summary | ||||||
| Calculated from the Program and Grossing tabs. Change inputs there. | ||||||
| Totals | ||||||
| Net area, total (m²) | 1,097.5 | |||||
| Department gross area (m²) | 1,263.9 | |||||
| Building gross area (m²) | 1,491.4 | |||||
| Net-to-gross ratio | 73.6% | |||||
| Area added by grossing (m²) | 393.9 | |||||
| Spaces listed (rows on the Program tab) | 21 | |||||
| Target building gross area (m²) | 1,250 | |||||
| Difference from target (m²) | 241.40 | |||||
| By department (summary %) | ||||||
| Department | Net area (m²) | Share of net | Department gross (m²) | Share of department gross | Building gross, allocated (m²) | Net-to-gross, allocated |
| Public | 403.5 | 36.8% | 476.1 | 37.7% | 561.8 | 71.8% |
Showing the first 16 of 23 rows and 7 of 7 columns. Cells with formulas show the formula on hover.
| Space program calculator (net to gross) |
| Notes: what this workbook does, how to use it and the method behind it. |
| What it does |
| Turns a list of spaces into net, department gross and building gross areas. Each space's net area is multiplied by its quantity, departments add their own circulation and walls, and the building adds shared circulation, lifts, stairs, plan… |
| How to use it |
| 1. On the Program tab, list each space with its department, quantity and net area per space. Use the department names from the drop-down list. |
| 2. On the Grossing tab, set the grossing factor for each department and the building grossing factor from your planning standard. |
| 3. Enter the target building gross area from the brief. |
| 4. Read the totals, the net-to-gross ratio and the difference from target on the Summary tab. |
| 5. Use the share columns to see which departments take the largest share of the net and gross areas. |
| Formulas and method |
| Total net area for a space = quantity × net area per space. |
| Department gross area = department net area × (1 + department grossing factor). Department net areas are SUMIF totals of the Program tab. |
Showing the first 16 of 32 rows and 1 of 1 columns. Cells with formulas show the formula on hover.
About this template
This calculator turns a list of spaces into net areas, then into department and building gross areas. Each space's net area is multiplied by its quantity. Each department adds its own grossing for internal circulation, walls and services, and the building adds a grossing factor for shared lobbies, lifts, stairs, shafts, plant and external walls.
The summary tab reports the totals, the net-to-gross ratio and the difference from a target building gross area. It also gives each department's share of the net and the gross area, and a building gross allocated to departments in proportion to their gross area, so the allocated figures add back to the total.
The example describes a fictional community learning centre with 21 space rows across five departments and a target of 1,250 square metres. Change the spaces and factors to match your brief. The factors are planning allowances, not measured values; confirm them with the client or the planning standard you work to.
What’s inside
- Net area per space × quantity, totalled by department with SUMIF
- Department grossing factor applied to each department's net area
- Building grossing factor applied to the total department gross area
- Net-to-gross ratio and difference from a target building gross area
- Summary shares by department, with an allocated building gross that adds up
Tabs
| Tab | What it holds |
|---|---|
| Program | Spaces by department with quantity, net area per space and total net area. |
| Grossing | Department grossing factors, building grossing factor, building gross area and comparison with the target. |
| Summary | Totals, net-to-gross ratio, and each department's share of net and gross area. |
| Notes | What the workbook does, how to use it, the grossing method, the assumptions and the professional-verification note. |
How to use it
- On the Program tab, list each space with its department, quantity and net area.
- On the Grossing tab, set the grossing factor for each department from your planning standard.
- Set the building grossing factor for shared circulation and services.
- Enter the target building gross area from the brief.
- Read the totals, the net-to-gross ratio and the department shares on the Summary tab.
Good for
- Testing whether a programme fits a target gross area
- Converting a room list into the gross area a client quotes
- Comparing departments by share of net and gross area
- Checking the net-to-gross ratio at early programming
Questions about this sheet
What is the difference between department and building grossing?
Department grossing covers circulation and walls inside each department. Building grossing covers the shared parts of the building, such as lobbies, lifts, stairs, shafts and plant.
Why is the allocated building gross different from the department gross?
The allocated figure adds the building grossing factor to each department in proportion to its gross area, so the allocations sum to the building gross.
Can I add a department?
Insert a row in the Grossing table, name the department exactly as it appears on the Program tab, and enter its factor. The check cell on the Grossing tab confirms that every department is counted.
Are the grossing factors standard?
They are example planning allowances. Use the figures from your brief, client or the area definitions in your jurisdiction.