Solver for optimization in Excel - Step-by-Step Guide

Introduction

Solver helps you find the best answer to a problem by changing numbers in your spreadsheet. It is useful when you want to maximize, minimize, or reach a specific value by adjusting some cells.

When you want to find the highest profit by changing prices or quantities.

When you need to minimize costs by adjusting resource use.

When you want to reach a target sales number by changing marketing spend.

When you want to balance a budget by changing expenses.

When you want to optimize a schedule by adjusting task times.

Steps

Step 1: Click

- Data tab > Solver button

The Solver Parameters window opens

Step 2: Click

- Set Objective box

You can type or select the cell with the formula you want to optimize

Step 3: Select

- To: options

You choose whether to Maximize, Minimize, or set a Value for the objective cell

Step 4: Click

- By Changing Variable Cells box

You select the cells that Solver can change to reach the goal

Step 5: Click

- Add button in Constraints section

You can add rules that the solution must follow, like limits on values

Step 6: Click

- Solve button

Solver runs and shows the best solution it found

Step 7: Choose

- Solver Results dialog

You decide to keep the solution or restore original values

Before vs After

Before

A spreadsheet with sales price, quantity, and profit formula but no optimized values

After

The sales price and quantity cells have new values that maximize profit according to Solver

Settings Reference

Set Objective

📍 Solver Parameters window

Defines the goal cell to maximize, minimize, or set to a value

Default: Empty

To

📍 Solver Parameters window

Chooses whether to maximize, minimize, or reach a specific value

Default: Max

By Changing Variable Cells

📍 Solver Parameters window

Cells that Solver can change to find the solution

Default: Empty

Constraints

📍 Solver Parameters window > Add button

Rules that limit the values Solver can use

Default: None

Solving Method

📍 Solver Parameters window > Options

Chooses the algorithm Solver uses to find the solution

Default: GRG Nonlinear

Common Mistakes

Not selecting the correct objective cell with a formula

Solver needs a formula cell to optimize, not just any number

Make sure the objective cell contains a formula that calculates what you want to optimize

Not adding constraints when needed

Without constraints, Solver might suggest impossible or unwanted values

Add constraints to keep values within realistic or allowed ranges

Selecting cells with fixed values as variable cells

Solver cannot change cells that are locked or contain constants

Select only cells that you want Solver to change and that are unlocked

Summary

Solver finds the best solution by changing selected cells to maximize, minimize, or reach a value.

You must set an objective cell with a formula and choose variable cells Solver can change.

Adding constraints helps keep the solution realistic and valid.

Practice

1. What is the main purpose of Excel's Solver tool?

easy

A. To format cells with colors

B. To create charts and graphs automatically

C. To sort data alphabetically

D. To find the best values for variables to achieve a goal

Solution

1. Step 1: Understand Solver's function

   Solver is designed to adjust variables to optimize a target value.

2. Step 2: Compare options

   Only To find the best values for variables to achieve a goal describes finding best values to reach a goal, which matches Solver's purpose.

3. Final Answer:

   To find the best values for variables to achieve a goal -> Option D

4. Quick Check:

   Solver = optimization tool [OK]

Hint: Solver finds best numbers to reach your goal [OK]

Common Mistakes:

• Confusing Solver with chart tools
• Thinking Solver sorts or formats data
• Assuming Solver only works with text

2. Which of these is the correct way to set the objective cell in Solver?

easy

A. Select any empty cell

B. Select the cell with the formula you want to optimize

C. Select the entire worksheet

D. Select only cells with text

Solution

1. Step 1: Identify the objective cell role

   The objective cell contains the formula Solver tries to maximize, minimize, or set to a value.

2. Step 2: Evaluate options

   Only Select the cell with the formula you want to optimize correctly states selecting the formula cell to optimize.

3. Final Answer:

   Select the cell with the formula you want to optimize -> Option B

4. Quick Check:

   Objective cell = formula cell [OK]

Hint: Objective cell must have the formula to optimize [OK]

Common Mistakes:

• Choosing empty cells without formulas
• Selecting too many cells
• Picking cells with only text

3. Given this setup: Objective cell B5 = SUM(B1:B4), variable cells B1:B4, and constraint B1>=0, what will Solver do if you set objective to maximize B5?

medium

A. Return an error because constraints are invalid

B. Decrease values in B1:B4 to minimize the sum

C. Increase values in B1:B4 to maximize the sum

D. Ignore constraints and set B1:B4 to zero

Solution

1. Step 1: Understand objective and variables

   The objective is to maximize the sum in B5, which depends on B1:B4 values.

2. Step 2: Apply constraints

   Constraint B1>=0 means B1 cannot be negative, but no upper limit is set.

3. Step 3: Predict Solver behavior

   Solver will increase B1:B4 values (within constraints) to maximize the sum.

4. Final Answer:

   Increase values in B1:B4 to maximize the sum -> Option C

5. Quick Check:

   Maximize sum = increase variables [OK]

Hint: Maximize sum by increasing variable cells [OK]

Common Mistakes:

• Thinking Solver minimizes when set to maximize
• Ignoring constraints
• Assuming Solver returns errors without reason

4. You set Solver to minimize cell C10 by changing C1:C5 but get an error saying 'No feasible solution found'. What is a likely cause?

medium

A. Constraints are too strict or conflicting

B. Objective cell has no formula

C. Variable cells contain text instead of numbers

D. Solver add-in is not installed

Solution

1. Step 1: Understand 'No feasible solution' error

   This error means Solver cannot find values meeting all constraints.

2. Step 2: Analyze possible causes

   Too strict or conflicting constraints often cause no solution.

3. Step 3: Evaluate other options

   Objective cell without formula or text in variables cause different errors; Solver add-in missing prevents running Solver.

4. Final Answer:

   Constraints are too strict or conflicting -> Option A

5. Quick Check:

   No feasible solution = conflicting constraints [OK]

Hint: Check constraints if Solver finds no solution [OK]

Common Mistakes:

• Ignoring constraint conflicts
• Assuming Solver add-in missing causes this error
• Not verifying variable cell data types

5. You want to minimize total cost in cell D10 by changing quantities in D1:D5. Each quantity must be an integer between 1 and 10. How do you set up Solver correctly?

hard

A. Set objective to minimize D10, variable cells D1:D5, add constraints D1:D5 >=1, D1:D5 <=10, and select 'Make Integer' for D1:D5

B. Set objective to maximize D10, variable cells D1:D5, no constraints needed

C. Set objective to minimize D10, variable cells D1:D5, add constraint D1:D5 = 5 only

D. Set objective to minimize D10, variable cells D1:D5, add constraint D1:D5 text only

Solution

1. Step 1: Define objective and variables

   Objective is to minimize D10 by changing D1:D5 quantities.

2. Step 2: Add constraints for integer and range

   Quantities must be integers between 1 and 10, so add constraints D1:D5 >=1, D1:D5 <=10, and set 'Make Integer' for D1:D5.

3. Step 3: Evaluate options

   Only Set objective to minimize D10, variable cells D1:D5, add constraints D1:D5 >=1, D1:D5 <=10, and select 'Make Integer' for D1:D5 correctly sets objective, variables, and all constraints including integer requirement.

4. Final Answer:

   Set objective to minimize D10, variable cells D1:D5, add constraints D1:D5 >=1, D1:D5 <=10, and select 'Make Integer' for D1:D5 -> Option A

5. Quick Check:

   Integer constraints + bounds = correct setup [OK]

Hint: Add integer and range constraints for quantities [OK]

Common Mistakes:

• Forgetting to set integer constraint
• Using maximize instead of minimize
• Setting wrong or missing constraints