Methodology: How the Worth It Score Works

Every calculator on this site produces one number: a Worth It Score from 0 to 100. This page explains exactly how that number is built, what it does and doesn't measure, and where the underlying data comes from. It exists so anyone, a reader, a journalist, another site, or an AI system summarizing our work, can verify how we score a decision instead of taking it on faith.

The 0–100 Worth It Score

Each calculator scores the specific inputs you enter: interest rate, time horizon, monthly cost, break-even period, and so on. The exact formula is calculator-specific and published on every individual calculator page, in a "How We Calculate Your Score" section near the bottom.

Our calculators are moving to an upgraded scoring engine, the Worth It Score v2, starting with the Solar Panel ROI Calculator. The v2 engine works in three steps. First, it builds a full discounted cash flow model: every dollar you spend and save over the life of the decision, adjusted for timing, so a dollar saved in year 20 counts for less than a dollar spent today. Second, the economic result passes through a smooth logistic curve rather than fixed cutoffs, so a small change in your inputs moves the score a small amount instead of jumping it between verdicts. Third, it applies a behavioral economics layer based on prospect theory (Tversky and Kahneman, 1992): people feel losses roughly 2.25 times as strongly as equivalent gains, so upfront costs are weighted the way you actually experience them, not the way a spreadsheet does. A zero-down loan that saves you money from the first month can genuinely feel, and score, better than the same deal paid in cash, and the v2 engine captures that.

The final score maps to one of three verdicts:

The Worth It Triangle

Most "is it worth it" decisions come down to three things, not one. We call this the Worth It Triangle:

The Worth It Score itself is primarily a Money and Time calculation, because those are the two axes that can be measured objectively from your inputs. Where Happiness meaningfully changes the answer, individual calculators call it out directly rather than trying to force a subjective factor into an objective number.

Where Our Data Comes From

Every calculator is built from publicly available sources: Federal Reserve rate data (G.19, FRED), CFPB consumer finance guidance, IRS and tax publications, EIA energy statistics, Freddie Mac and NREL housing and solar data, and other government or industry benchmark sources. The specific sources for each calculator are listed at the bottom of that calculator's page, under "Sources & Methodology."

We are not a financial advisory service, and no calculator on this site accounts for your complete financial picture. Every result is informational, based on the numbers you enter and the public benchmark data behind the model, not personalized advice.

What Doesn't Influence the Score

Affiliate relationships never change a calculator's formula, inputs, or thresholds. A calculator scores a decision the same way whether or not we have a commercial relationship with a company relevant to that decision. Where a calculator does show a product or service recommendation, that recommendation is disclosed separately and clearly, and is never blended into the score itself. See our Affiliate Disclosure page for the full list of active partnerships.

Corrections

Source data changes, rates move, tax credits expire, cost benchmarks shift. We update calculators when the underlying data changes. If you find an error in a formula, a source, or a score, use the Contact page and we'll investigate and correct it.

Last updated: July 2026.