BiGO interpreter and BiGO script together (*the tool*) calculate the upper bounds for primitive recursive functions. BiGO script is a notation language that is used to model the program flow execution in the terms of the time steps. BiGO interpreter is not acutally an interpreter, although it has
some common characteristics with programming language interpreters; after creating the parse tree from a given BiGO script, the evaluator calculates the Big O from the parse tree without executing the given BiGO script. BigO script is complete to *context sensitive languages*.
The documentation and syntax with examples can be found from the tool. The tool is available for MacOS, Linux and for Windows (x64).

- Arithmetic operations
- Functions such as (...)
^{(...)}, log_{k}(...) etc. - Loops through repeat structures and recursion
- Binary / Unary types for non-constant time operations

- Projects
- Importing Java / Python source code (with the sections commented via BiGO script syntax)
- Syntax highlighting
- Graphs for the functions in comparison to widely known upper bounds
- Big O as TeX and function
- Estimates for running time of a function / project
- Examples of basic algorithms such as sorting and tree traversal and examples of some more complex algorithms such as DPLL
- Highlighting of the function variables for both source and the O(...)