Tablora · Library
Convert a stated percentage to its decimal value
A percent sign changes the scale: 12,5% becomes 0.125, not 12.5. See how the normalizer shifts the digits and what to check downstream.
A percent sign is a scale, not decoration
Rates, discounts, shares and growth figures often arrive with a percent sign: 12,5% or 4.75%. Deleting the sign leaves 12.5, which is a hundred times too large if the receiving sheet expects a fraction. The numeric normalizer treats a trailing percent sign as part of the value's meaning and converts the number to its decimal form.
It does this by moving the decimal mark two places to the left in the digits themselves, so no rounding or floating-point arithmetic is involved.
12,5% under a decimal comma
The page example uses Decimal separator , and Grouping separator . with the source value 12,5%. The result is 0.125. The comma is read as the decimal mark, the percent sign is removed and the value is scaled, giving three decimal places.
Under the same settings, 100% would become 1.00 and 0,5% would become 0.005. A space before the percent sign, as in 12,5 %, is accepted as well.
Because the shift works on the digits, the result can have more decimal places than the source: 12,5% has one decimal place and 0.125 has three. That is the exact value, not a rounding effect, and it is worth keeping when the rate is later multiplied by an amount.
Converting a rate column
- Make sure the values in the source actually carry a percent sign; a rate column written without one is already a plain number and is not scaled.
- Choose the Decimal separator the column uses, and the Grouping separator if large percentages are grouped.
- Pick the rate column in Number column and press Calculate.
- Spot-check the scaled results against the source: 12,5% should read 0.125, not 12.5 or 0.0125.
- Decide how the receiving sheet expects rates before you paste the results there.
- A per mille sign or a word such as pct is not recognized; those values are held for review.
Mistakes with percentage columns
- Multiplying the result by 100 again because it looks small. Only do that if the receiving field explicitly wants percentage points.
- Mixing rows with and without a percent sign in one column: the ones without are not scaled, so the column ends up on two different scales.
- Formatting the output as a percentage and forgetting it is already a fraction.
- In the Tablora app, the XLSX export also divides percentage cells by 100 in columns it treats as numbers and gives them a percentage format, so the cell holds 0.125 but displays as 12.50%. If you then copy the displayed value elsewhere, you are copying the formatted text, not the fraction.
Original synthetic example
- Source value
- 12,5%
- Decimal separator
- ,
- Grouping separator
- .
- Expected outcome
- Normalized amount: 0.125