Logits

The raw score each candidate gets before becoming a probability

Key points
  • Logits are the unsorted score each candidate gets, right before the model picks an answer.
  • They don't add up to 100 percent, and some are negative. On their own, they aren't probabilities.
  • What matters isn't a score's raw size but the gap between candidates. A big gap means one candidate has essentially won.
  • The calculation that turns these scores into probabilities is softmax. It doesn't change the ranking.
  • Adjustments like temperature or banned words mostly happen right here, on this scoreboard, before it becomes a probability.
Contents

1The analogy

The workbench at a neighborhood electronics repair shop is lined with broken devices. To find the fault, the owner touches a meter to each part and writes down exactly how far the needle swings. What's written on that paper isn't meant for a customer to see — some numbers are large, some are negative, and one line alone doesn't mean anything on its own. There's only one thing the owner does with this paper: compares which part looks more suspicious than another.

The scoreboard a model builds right before choosing the next piece is this paper. Every candidate gets one number, they don't add up to 100, and some are negative. Even so, this paper alone is enough to tell which candidate is ahead.

To say "there's an X percent chance it's this part," one more calculation is needed. That calculation is softmax.

2In detail

The last step hands out one score per candidate

The model keeps reshaping values as a sentence passes through it, then runs one more calculation at the very end to produce a row of numbers. That row is exactly as long as the number of pieces the model knows — tens of thousands of pieces means tens of thousands of scores.

Each entry stands for "how likely this piece is to come next." A larger value means the model favors that piece; a small or negative one means it doesn't fit the current spot.

These numbers aren't written for a person to read. They're a direct byproduct of computation happening inside the model, with no fixed scale or reference point of their own.

The scores aren't probabilities yet

Logits differ from probabilities in three ways: they don't sum to one, they can be negative, and they have no upper or lower bound. So one score alone can't tell you "how confident is the model in this answer."

What matters is the gap between candidates. A wide gap between first and second place means the answer has essentially settled; scores bunched close together means several outcomes would all be unsurprising. Add the same amount to every score and this gap stays exactly the same, so the result doesn't change either.

Turning scores into probabilities is a separate step

Turning the scoreboard into probabilities means dividing the whole set at once. One candidate's score alone can't tell you a percentage — the scores every other candidate received matter too. If the rest score low, the same score becomes a high probability; if everyone scores similarly high, the probability splits thin.

This conversion never touches the ranking. Whoever led on the scoreboard still leads after becoming a probability. Probability isn't built to set the order — it's built to give people a scale they can read and compare, and it's also the form needed to randomly pick an answer and add some variety.

Most dials reach into this scoreboard

Settings that shape an answer's character usually step in before scores turn into probabilities. Raising temperature narrows the gap between candidates' scores, so once turned into probabilities, lower-ranked candidates become plausible picks too. Lowering it widens the gap, making the top candidate nearly a lock.

Blocking a specific word from appearing works here too — push that piece's score down far enough and it's effectively zero once it becomes a probability. Discouraging repeated words works the same way, by shaving a little off the score of pieces that already appeared.

That makes it clear where to look when an answer goes wrong: whether the model's own scores are the problem, or whether an adjustment tacked on afterward is.

3More precisely

Logits are the row of numbers, as long as the piece list, that comes out of a model's final computation. Because they haven't been turned into probabilities yet, they're described as unnormalized. The name comes from a function statistics once used to turn probabilities into scores, and it's now settled into meaning the score right before a probability — a leftover of the math, not a description of what it does.

The analogy breaks down in places. The repair shop owner knows exactly what basis they used to write each number down, but a model's scores carry no such record — why one piece scored high isn't visible from the numbers alone. A meter reading can also be taken for one part at a time, while logits always come out as one bundle covering every candidate at once. And a high score doesn't mean something is true — a phrase seen often tends to score high, so an incorrect sentence can easily score well too. That property survives the trip into probabilities, so a high probability should never be read as confidence in accuracy.

4Try it yourself

5Common misconceptions

  • It's easy to think logits are already probabilities, but actually they're an unsorted set of scores that don't sum to one and can be negative.

  • It's easy to think a high score means a correct answer, but actually it only means the piece fits that spot, which is a separate question from whether it's true.

  • It's easy to think turning scores into probabilities changes the ranking, but actually the order stays exactly the same and only the scale changes.

7One-line summary

In shortLogits are the unsorted scoreboard a model writes down for every candidate, and turning that scoreboard into probabilities a person can read is the calculation that comes right after.

Spotted an error or have a better analogy? Suggest an edit · Last updated2026-09-02