Custom Formulas allows you to store custom equations with multiple variables that you can use again and again. Unlike a lot of other apps that try to replicate a scientific calculator, Custom Formulas has been designed around the iPhone and provides a clean simple interface. All of your custom equations are available on the main launch window and with one simple click you can be entering data and getting the results you want. So what can you use it for? Well that comes down to you as Custom Formulas gives you the flexibility to create anything that you need. For example:
- Split a restaurant bill including a 15% tip
- Monthly mortgage payments
- Generate random lottery numbers from 1 to 40
- Your secret formula that you use to find the best value rental property
- Optimal firing distance for your death ray

Features
- Up to four variables can be used (and individually named)
- A good selection of functions (see below)
- Multiple levels of parentheses are supported
- Example equations provided
- Optimized for iPhone 5

Available Functions
- add
- subtract
- multiply
- divide
- square root
- random number
- power function
- cosine
- sine
- tangent