THE NUMBERS, EXPLAINED
How to use this calculator.
Constant-quantity basket with exactly matched items; substitutions must be converted to comparable unit quantities before entry. Index base is 100.
Start with your inputs
Enter fixed basket quantities, base-period unit prices, current unit prices. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Fixed basket quantities | 2,3 |
| Base-period unit prices | 5,10 |
| Current unit prices | 6,12 |
A worked example
With the example inputs above, base basket cost is 40. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Base basket cost | 40 |
| Current basket cost | 48 |
| Price index (base 100) | 120 |
How this is calculated
Base basket cost
Multiply fixed quantities by base prices and sum.
Current basket cost
Price the same quantities at current prices.
Price index (base 100)
Divide current basket cost by base cost and multiply by 100.
Symbols and units
- a
- Fixed basket quantities
- b
- Base-period unit prices
- c
- Current unit prices
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
Constant-quantity basket with exactly matched items; substitutions must be converted to comparable unit quantities before entry. Index base is 100.
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?
Base basket cost; Current basket cost; Price index (base 100). 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: Constant-quantity basket with exactly matched items; substitutions must be converted to comparable unit quantities before entry. Index base is 100.
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.
Read the quality report →