OpenSolver is a free add-in that's a powerful alternative to Excel's Solver add-in.
Overview of OpenSolver:
OpenSolver is an Excel VBA add-in that extends Excel's built-in Solver with more powerful solvers.
OpenSolver provides the following features:
OpenSolver.org. "About OpenSolver"
- OpenSolver offers a range of solvers for use in Excel, including the excellent, Open Source, COIN-OR CBC optimization engine which can quickly solve large Linear and Integer problems.
- Compatible with your existing Solver models, so there is no need to change your spreadsheets.
- No artificial limits on the size of problem you can solve – have as many variables and constraints as your computer memory allows (but be aware that large problems can be slow to solve).
- OpenSolver is free, open source software.
For more information: OpenSolver