How we rate compatibility
Every pairing on this site carries one of five words: excellent, strong, good, moderate or challenging. This page says where that word comes from, in enough detail that a reader can work it out and disagree with it.
What goes in
Two four-letter codes. That is the entire input. Not the answers behind them, not an age, not how long the two people have known each other, not anything either of them has ever done. The two codes are compared letter by letter, and the whole comparison is four yes-or-no questions: do they share the first letter, the second, the third, the fourth.
How four answers become a word
Each context starts from a base number. Every letter the two codes share, or do not share, adds a fixed amount to it. The total is held between 35 and 95, and the band is whichever range it lands in.
The four contexts use different weights, which is why one pairing can read strong for work and moderate for romance. Sharing the second letter counts for most everywhere: two people who take in information the same way tend to describe talking to each other as easy, and that is the thing this framework is least bad at.
| Context | Starting points | Same letter | Different letter |
|---|---|---|---|
| Overall | 55 | E/I -2, S/N +18, T/F +8, J/P +8 | E/I +6, S/N +0, T/F +0, J/P +0 |
| Romance | 50 | E/I +4, S/N +18, T/F +5, J/P +8 | E/I +12, S/N +0, T/F +12, J/P +4 |
| Friendship | 55 | E/I +4, S/N +16, T/F +14, J/P +8 | E/I +0, S/N +0, T/F +0, J/P +0 |
| Work | 55 | E/I +0, S/N +12, T/F +8, J/P +14 | E/I +6, S/N +0, T/F +0, J/P +0 |
The cut-offs
The score is read off this table.
| Rating band | Total score |
|---|---|
| Excellent match | 85 and above |
| Strong match | 75 and above |
| Good match | 65 and above |
| Moderate match | 55 and above |
| Challenging match | below 55 |
A worked example
Take INFJ and ENFP. The two codes share S/N and T/F and differ on E/I and J/P. Run them through the table above and each context adds up like this: the starting points first, then one number for each letter in E/I, S/N, T/F, J/P order.
- Overall: 55 +6 +18 +8 +0 = 87, Excellent match
- Romance: 50 +12 +18 +5 +4 = 89, Excellent match
- Friendship: 55 +0 +16 +14 +0 = 85, Excellent match
- Work: 55 +6 +12 +8 +0 = 81, Strong match
Work comes out lowest for this pair. The work weights put 14 points on a shared fourth letter, more than any other letter earns in that row, and INFJ leans toward settling plans early while ENFP leans toward keeping them open. Nothing about the two people changed between the rows; the same four letters were simply weighed for a different setting.
How low each context can go
Several contexts give nothing, or next to nothing, for a difference, so the bottom of the scale is out of their reach. Across all 120 pairings of two different types, this is the lowest band each context ever gives, with one pairing that lands there:
- Overall: Challenging match, for example INTJ and ISFP
- Romance: Moderate match, for example INTJ and ISTP
- Friendship: Moderate match, for example INTJ and ESFJ
- Work: Moderate match, for example INTJ and ISTP
A band that a context never reaches says something about the weights, not about anyone's relationships: the arithmetic for that setting cannot produce it. It is also why a pairing with nothing in common still reads moderate for friendship, where a difference is worth zero rather than a penalty.
The numbers were chosen, not measured
This is the part most sites leave out. Every number on this page was picked by hand when the site was built. None of it is fitted to a data set, none of it comes from a study, and nobody has checked whether it predicts anything at all about two real people.
There are reasons behind the ordering. A shared second letter is weighted heaviest because agreement about what is worth paying attention to is what people describe when they say someone is easy to talk to. Work leans on the fourth letter because deadlines are where planners and improvisers actually collide. Romance rewards differing on the third letter because one person who leads with logic and one who leads with values often cover for each other. Those are arguments, not evidence, and an argument does not become a finding by being turned into a number.
The site used to print a percentage instead. Eighty-seven per cent reads like a measurement of a couple, and four letters cannot carry two digits of precision. A word can be read literally without claiming more than it has.
What it is not
It is a rule of thumb about two labels, not a forecast about two people. A challenging band is not a warning and an excellent one is not a recommendation. The four letters leave out everything that actually decides how two people get on, so treat the band as a conversation starter and nothing heavier.
Questions about the bands
Why can two different types collect more points than two of the same type?
Because in some settings a difference earns more than a match. Two people of the same type share all four letters, so they only ever collect the same-letter column of the table. In romance, a different first or third letter is worth more than the same one, so a pair that differs there can end up with more points than a pair that matches on everything, even when both land in the same band. That is a consequence of the weights, not an observation about couples.
Does it matter how strongly I lean toward each letter?
Not to the band. The rating reads the four letters and nothing else, so a preference you landed on by a few points counts exactly like one you landed on by a wide margin. If either of you came out near the middle on a preference, a retake could flip that letter and move the band with it. The percentages on your own result page show how close each call was, and they are worth a look before a band is taken to heart.
Can the numbers change?
Yes. If a reader makes a convincing case that a weight is wrong, it gets changed. Every band on the site and both tables on this page read the same set of numbers, so a change shows up everywhere the next time the site is updated. No single pairing ever has its band set by hand.
If you think a band is wrong, tell us why: support@onlinembtitest.com