What Plumline can solve, check and explain

Plumline reads a linear optimisation model from a spreadsheet-style grid and solves it directly in your browser. See which decisions it can model, what it checks after solving, and how it helps you understand the result.

Open the solver

Runs locally
No account
Five languages
Checked against your formulas

Illustration of a production planning model, showing decision cells and detected decision variables.

Models you can solve

Model type	Use it when	Example
Continuous models	Use decimal values when a decision can be divided, such as hours, weight, distance or budget.	Try a production plan
Integer models	Use whole numbers for decisions such as people, vehicles, batches or units produced.	Open workforce scheduling
Binary decisions	Use 0 or 1 for choices such as selecting a project, opening a site or accepting an order.	Try project selection
Mixed-integer models	Combine decimal values, whole numbers and binary choices in the same model.	Try supplier activation

Continuous models: Plumline accepts linear relationships only. It stops and identifies formulas that are genuinely nonlinear.

Integer models: Proving the best result can take longer as an integer model grows.

Maximise or minimise

Choose whether Plumline should find the highest value or the lowest cost, time, distance or waste.

Learn how to set decision types

Works with your spreadsheet

Paste your model

Copy a range from Excel or Google Sheets and paste it into the grid.
Adjust it

Set fixed or formula-based limits, then choose whether to maximise or minimise.
Export the result

Download as CSV or Excel, or copy a plain text summary.

Learn how to structure your model

Checks built into every result

Illustration of a checked result, showing the objective and constraints checked again, together with the solution status. — An illustration of how Plumline checks the objective, constraints and solution status after solving.

Every result is checked against your own formulas

Objective checked again

After solving, Plumline recalculates the objective from your formulas and compares it with the reported value.

Constraints checked again

Plumline substitutes the solved values into every constraint and shows whether each one is satisfied.

Solved in your browser

Your model is processed in the browser. Plumline does not upload it to a server.

Understand solution statuses

Understand the answer

Illustration of a two-variable feasible region with its optimal point marked. — An illustration of a two-variable feasible region and its optimal solution.

See what Plumline understood

Before solving, Plumline shows the objective, decision cells and constraints it detected. You can correct anything that does not match your model.

Marginal impact

For eligible continuous models, Plumline estimates how the objective may change when a binding constraint is loosened by one unit.

When this appears This estimate is shown only for eligible binding constraints in continuous models.

Feasible region chart

For models with two decision variables, Plumline can draw the feasible region and show whether it is bounded or extends without a finite limit.

When this appears The chart appears only when the model can be represented reliably within the supported display range.

View the feasible region

Five interface languages

Use Plumline in English, Spanish, Portuguese, German or French.

Messages in the selected language

Solver and engine messages follow the language selected in Plumline.

Learn how Plumline explains a result

Try Plumline with a real model

Open one of the examples above or paste your own spreadsheet model into the solver. Plumline will show what it understood before solving and check the result afterwards.