Own-assumption purchasing power
Choose your annual inflation rate and years, or two manually entered indices. Show nominal equivalent separately from purchasing power.
- Runs in your browser
- No upload
- Check before download
Choose your annual inflation rate and years, or two manually entered indices. Show nominal equivalent separately from purchasing power.
Calculations run locally and inputs are not saved automatically. Download an input backup before closing the tab. Input data, formulas and filenames are never sent. Only with your optional consent, Refentra sends aggregate counts of actions and outcomes, without input content.
What are the limits?
Maximum amount 1 trillion units; total 100 trillion cents. Up to 100 rows, 50 people, 20 tiers, 100 depreciation years, 1,200 schedule periods, 61 cash flows. IRR range −99% to 1,000% per interval, numerical candidates only. Rates: up to eight decimals. Backup: 1 MiB. CSV formula-leading text gets an apostrophe. Use decimal points, no thousands separators.
Amounts use two decimals in your stated unit. Exact decimal inputs; cent rounding half away from zero. Table sums balance. Largest fractional remainders receive shared cents; equal remainders use row order. No tax, fees, legal entitlement or current prices are inferred.
Non-monetary values are shown with up to ten significant digits. CAGR, fractional-year inflation and IRR use numerical approximations; IRR candidates are not a symbolic proof. CSV keeps the numeric values before display rounding.
f_r = (1+r)^n; f_I = I₁/I₀; A_nom = A × f; A_real = A/f
Calculate with your own assumptions
- Enter the inputs
Choose a constant annual rate, or two index values from the same index series. Enter a starting amount. Neither option downloads actual inflation data. Enter decimals with a point and without thousands separators.
- Check a worked example
Amount 100, annual rate 10%, years 2: factor 1.1²=1.21. The matching future amount is 121, and the purchasing power of an unchanged 100 is 100/1.21≈82.64. An index going from 100 to 121 gives the same factor.
- Interpret and save the result
The nominal result multiplies by the price factor and the real result divides by it, so they answer opposite questions. Export both values together with the assumptions you chose. Results for fractional years are numerical approximations.
Method, errors and limits
Can I reopen editable inputs from the CSV?
The CSV is a report of the results, not a backup of your inputs. Download the separate JSON input backup before you close the page, then import it into this same tool to edit your assumptions again. Import accepts files up to 1 MiB and checks that the file belongs to this tool. Inputs are not saved automatically.
Which input mistakes should I check?
Both indices must be positive and comparable, so don't mix series that were rebased differently. Rate mode accepts −99% to 1000% and 0–1000 years. Enter 10 for 10%, not 0.10.
What are this model’s limits?
A scenario, not an inflation forecast or a lookup of an official index. One constant rate can't represent yearly rates that change. Very large factors outside the numeric and money limits are rejected.