Percentage Calculator

This tool computes three common percentage scenarios from numeric inputs: percent_of_value, percent_of_total, and percent_change. It operates without external data sources and supports unit-agnostic arithmetic.
Conceptually, it applies straightforward formulas and returns results with consistent precision. For percent_of_value, result = total × percent / 100. For percent_of_total, percent = part ÷ total × 100. For percent_change, change = (new − old) ÷ old × 100.
Users include students solving math problems, analysts comparing metrics, marketers calculating discount impacts, and finance teams validating budgets. Unique value lies in combining three related calculations in one tool and providing clear edge-case handling.
Core features include mode selection, explicit inputs per mode, numeric validation, and standardized output formatting. Edge cases like zero denominators and negative values are addressed to avoid misleading results.