Worked example
Operation: b% of a a: 200 b: 15
→ 30
Method and scope
Find a part, percentage, change or increase/decrease. For percentage change the old value a must be positive; percentages of a negative reference retain its sign.
a × b / 100; a / b × 100; (b − a) / a × 100; a(1 ± b/100)
Precision and limits
≈ marks an approximation. Display rounding does not change the internal calculation.