THE NUMBERS, EXPLAINED
How to use this calculator.
One resident per room. Divide shared area equally, add it to private area, apply agreed quality weights, then normalize to total rent. Amounts are before currency rounding.
Start with your inputs
Enter private room areas (m²), shared area (m²), agreed room quality weights, total rent. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Private room areas (m²) | 10,20 |
| Shared area (m²) | 30 |
| Agreed room quality weights | 1,1 |
| Total rent | 900 |
A worked example
With the example inputs above, weighted area scores is 25, 35. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Weighted area scores | 25, 35 |
| Rent shares | 375, 525 |
How this is calculated
Weighted area scores
Add equal common-area share to each room and apply its agreed weight.
Rent shares
Normalize weighted area scores to the total rent.
Symbols and units
- a
- Private room areas (m²)
- b
- Shared area (m²)
- c
- Agreed room quality weights
- d
- Total rent
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions and limits
One resident per room. Divide shared area equally, add it to private area, apply agreed quality weights, then normalize to total rent. Amounts are before currency rounding.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Weighted area scores; Rent shares. The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: One resident per room. Divide shared area equally, add it to private area, apply agreed quality weights, then normalize to total rent. Amounts are before currency rounding.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Further reading
OpenStax: Solve proportions and their applications ↗
Background reading; this does not imply endorsement or independent review of SumFizz.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
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