A 3.7 GPA is a straight A- (3.7) on the commonest American plus/minus 4.0 scale; College Board's high-school chart, which records whole letters only, puts an A at 90 to 100%, and UMBC awards cum laude to graduates between 3.5 and 3.7499. That reading holds only on the scale it is calculated on: the same B+ is worth 3.3 at some institutions in this index, 3.33 at others, 3.3333 at one and 3.5 at one with no minus grades, so a 3.7 earned in one place is not the same work as a 3.7 earned in another.
3.7 GPA meaning: the grades that produce it
On a plus/minus 4.0 scale a 3.7 is roughly a straight run of A- grades, weighted by credit hours rather than by course count. Oregon State states the arithmetic in the clearest published form on this shelf, printing its table as grade points per credit rather than as a bare lookup, which is why a three-credit course moves the average three times as far as a one-credit one. Nothing about that calculation is national: it is your institution's.
The same number on a different scale
South Carolina prints a scale with no minus grades, where a B+ is 3.5 rather than 3.3. Arizona State records an A+ at 4.33 while capping the cumulative average at 4.00. Memphis prints an A- at 3.84 where almost everyone else prints 3.67 or 3.7. A transcript producing 3.7 at one of those institutions would produce a different figure at the others on identical work, which is the single most useful thing to know before comparing your number with anyone else's.
Close to an honours threshold, and why that is not one number
At the top of the scale the published rules stop agreeing. A fixed-threshold institution such as UMBC tells a student exactly what summa cum laude takes. A percentile institution cannot: UMass Amherst awards it to the top five per cent of each school and publishes the realised cut-off afterwards, which for recent graduates has run close to 3.99 in some schools and lower in others.
Other questions people ask
Is 3.7 a good GPA?
Yes, against the published honors rules in this index: UMBC awards cum laude to graduates between 3.5 and 3.7499, which takes in a 3.7, and UConn's summa floor is exactly 3.7, with a class rank in the 95th percentile on top. Three institutions here publish no threshold at all, so your own registrar page decides it.
What is 3.7 GPA in letter grades?
On a plus/minus 4.0 scale, roughly a straight run of A- grades. On a scale without minus grades the mix is different, and on a scale recording an A+ above four it is different again.
Does a 3.7 mean the same everywhere?
No. A transcript line reading "GPA: 3.7" means only what that institution's scale says it means, and the scales differ. Two institutions in this index price a B+ 0.2 of a grade point apart, 3.3 at one and 3.5 at the other, which over a full transcript is worth more than the width of most honours bands.