Scientific Calculator
Free online scientific calculator with advanced features
About This Numeral System
Persian numerals (۰ through ۹) are used in Iran, Afghanistan (for Dari), and in some Pakistani Urdu contexts. They share the same ancestor as Eastern Arabic numerals but have distinct glyph forms — most visibly, the Persian 4 (۴), 5 (۵), and 6 (۶) differ from their Arabic counterparts. If you work with Persian, Dari, or Urdu documents, this calculator renders results in the numeral forms you expect.
Frequently Asked Questions
How do I calculate a percentage increase when the original number is negative?
Percentage change with a negative base is a common source of confusion. If revenue goes from -50 to +50, the formula gives (50 - (-50)) / |-50| × 100 = 200%. But if revenue goes from -50 to -25, the formula gives (-25 - (-50)) / |-50| × 100 = 50% — a 50% improvement even though the number is still negative. Always use the absolute value of the original number as the denominator to avoid sign errors.
What is the difference between percentage points and percent change?
Percentage points measure the absolute difference between two percentages. If an interest rate rises from 5% to 7%, that is a 2 percentage point increase — but a 40% relative increase (because 2 is 40% of 5). Financial news often confuses these: "rates rose by 2%" could mean either 2 percentage points (5% to 7%) or a 2% relative increase (5% to 5.1%). The Percentage Change mode on this calculator computes the relative change; use the Difference mode for percentage point comparisons.
How do I calculate reverse percentage — finding the original price before a discount?
If an item costs $80 after a 20% discount, the original price was not $96 (a common mistake). The $80 represents 80% of the original, so the original is $80 / 0.80 = $100. Use the "Reverse Percentage" mode: enter 80 as the final value and 20 as the discount percentage, and the calculator returns the original price of $100.
How do I calculate what percentage one number is of another?
Use the "Find Percentage" mode. Enter the part (smaller number) and the whole (larger number). For example, to find what percentage 25 is of 200, enter Part: 25 and Whole: 200. The calculator will show 12.5%.
What percentage calculations are available?
The percentage calculator handles six common calculations: percentage of a number, percentage change (increase/decrease), what percentage one number is of another, reverse percentage, adding a percentage to a number, and subtracting a percentage.
How do Persian numerals differ from Arabic numerals?
The most visible differences are in the digits 4, 5, and 6. Persian 4 (۴) looks like a small triangle, while Arabic 4 (٤) is more angular. Persian 5 (۵) looks like a small heart shape, while Arabic 5 (٥) is a circle. Persian 6 (۶) resembles a reversed 9, while Arabic 6 (٦) is a single dot above the line. If you are working with documents from Iran or Afghanistan, use the Persian mode. For documents from Egypt, Saudi Arabia, or the UAE, use the Arabic mode.