Merrin Decision Lab
Free tools for thinking a decision through
Calculators for weighing your options, built to show their working. Each one runs in your browser: no sign-up, nothing to install, and nothing you type is sent anywhere.
Tools
Decision matrix calculatorWeigh your options against the criteria that matter to you, see which comes out ahead, and how much it would take to change the answer.Or start from a decision
Each opens the decision matrix calculator with typical criteria already filled in.
How these tools work
The maths is on the page
Every result comes with the formula behind it and a breakdown you can check by hand. When a result is close, the tool says so instead of announcing a winner.
Your decisions stay with you
The tools run in your browser and save to it. There's no account, and nothing you enter is sent to Merrin. Export a decision as a file or a share link whenever you want it somewhere else.
Each one ends with questions
A few prompts follow the result, because the most useful moment is often when the number disagrees with your gut.