Kalkulator PPh 21 is an Android application developed by Solution Tap that helps users calculate their PPh 21 taxes. PPh 21 is a tax on income in the form of salaries, wages, honorariums, allowances, and other payments related to employment or positions, services, and activities carried out by individual taxpayers in Indonesia.

The app offers two calculation methods: Gross Up and Non-Gross Up. The Gross Up method calculates the gross amount of income needed to receive a net income after tax, while the Non-Gross Up method calculates the tax amount from the net income. Kalkulator PPh 21 is a free application that falls under the Finance subcategory of Business & Productivity on the Google Play store.