How to Use Excel Solver

What this does

Solver is an optimiser: you give it a target cell, a set of cells it may change, and constraints, and it finds the values that maximise, minimise or hit a target. It ships with Excel but is off by default. It goes further than Goal Seek, which changes one input to hit one target with no constraints. Three solving methods are offered: Simplex LP for linear problems (fastest and guaranteed optimal), GRG Nonlinear for smooth curved ones, and Evolutionary for problems with IF, VLOOKUP or other non-smooth logic. Choosing Simplex LP on a nonlinear model produces an error; choosing GRG on a nonlinear model finds a local optimum that depends on the starting values. Before you run it on a workbook other people depend on, try it on a copy or a few rows first. Undo only reaches back through the current session, so a quick trial run is the cheapest way to see exactly what will change before the file is saved and shared. For “use excel solver”, the reliable version is a short checking loop, not just the first command that appears to work. Run it on a deliberately small range first, watch how the affected cells change, and only then apply the same setup to the full sheet. When this is a ribbon command, the selection matters more than the button: confirm the range, apply the command, then spot-check the output before saving. That is what makes a calculation you can defend to a CFO or an auditor useful in real work: repeatable, auditable, and not dependent on memory or luck.

A worked example

A production mix: profit per unit in B2:C2, hours per unit in B3:C3, total hours available 400 in E3. Units to make sit in B5:C5 (currently 0) and total profit in E5 as =SUMPRODUCT(B2:C2,B5:C5). Data ▸ Solver ▸ Set Objective: $E$5 ▸ To: Max ▸ By Changing Variable Cells: $B$5:$C$5 ▸ Add constraints: $E$3<=400 and $B$5:$C$5>=0, tick "Make Unconstrained Variables Non-Negative" ▸ Select a Solving Method: Simplex LP ▸ Solve. Solver writes the optimal units into B5:C5. Product mix, staff rostering, blending, transport routing and portfolio allocation are all the same shape of problem, and Solver answers them in one dialog instead of a week of trial and error. A practical tip: try it on a copy of the sheet or a handful of sample rows first and check the result before you apply it to the real data. That one habit catches almost every surprise while it is still cheap to reverse.

In Google Sheets

Solver is a Microsoft Excel add-in: load it with File ▸ Options ▸ Add-ins on Windows or Tools ▸ Excel Add-ins on Mac. Those steps do not apply to Google Sheets, which has no Excel Solver Add-in; optimisation in Sheets needs a separately installed Google Workspace Marketplace add-on (OpenSolver is one), with its own setup, options and limits. Nothing on this page is behind a login or a download: the exact answer is at the top, and the detail below it is there for when you need it. That is the whole promise here — the answer first, and just enough context to make it stick. Here is the takeaway for “use excel solver”: follow the steps at the top, check the result on the sheet itself, and keep undo in mind while you experiment. Done once deliberately, it becomes something you do from memory in Excel rather than something you search for again.

Common mistakes

• Putting a formula in a changing cell — Solver overwrites it with a number and the model breaks.
• Choosing Simplex LP for a model containing IF, MAX or a lookup, which reports that the linearity conditions are not satisfied.
• Leaving out a non-negativity constraint and getting an "optimal" answer that makes minus 300 units.
• Accepting a GRG Nonlinear result as the global optimum; it finds a local one, so re-run from different starting values.
• Expecting Solver in Excel for the web or on mobile, where the add-in does not exist.

Frequently asked questions