What is Percentage Calculator Online?
This tool handles four forms: (1) X% of Y, (2) X is what % of Y, (3) percentage change from X to Y, (4) reverse percentage (original value before % change). Used for SLA uptime targets, A/B test lift, conversion rate changes, and financial margins.
How to Use Percentage Calculator Online
- Select the calculation type.
- Enter the known values.
- Result appears instantly.
Example
Percentage of a value
Input
What is 15% of 200?Output
30Frequently Asked Questions
Formula for percentage change?
((New - Old) / Old) × 100. Positive = increase, negative = decrease.
What is 99.9% uptime in downtime hours?
0.1% downtime = 8.76 hours per year, or ~43.8 minutes per month.