See the number

This is the app, on a web page. Drag the marker to where your ball is. The big number is the distance from there to the center of the green, in whole yards. Tap Next when you get to the next tee. There is nothing else to learn.

What you are looking at

The drawing is a sketch: a strip of fairway, a green, a marker. The two points that matter are not sketched. The tee and the center of the green are the real mapped coordinates of hole 1 at Sherman Hills Golf Club in Brooksville, Florida, the course in our screenshots, and the number is the real great-circle distance between the marker and that green center, computed the way the app computes it. If you put the marker where our screenshot was taken, 148 yards short of the green, it reads 148, the same as the phone did.

Whole yards, always, and always to the center. Not the flag: the flag moves every morning and the middle does not, and on almost every green the middle is where an amateur should be aiming anyway. There is an argument for that in aim for the center of the green, with numbers.

Next and Previous walk you through the eighteen holes of the same course. The drawing changes; the geometry underneath is real for each one. A par 3 will look short because it is short.

What the real app adds

On the course the marker is you. The phone's GPS updates the number as you walk, and under open sky that fix is typically within about 5 meters, roughly 16 feet, according to GPS.gov; near trees it drifts more, and the app does not pretend otherwise. You start a round, pick your hole, and glance. The number is also on the Lock Screen and in the Dynamic Island while the round is on, so you can check it without unlocking anything.

Find My Course uses your location once to list the nearest mapped courses; or search by name. Once a course is loaded it works with no signal, because the course map ships inside the app and GPS needs no data. No account, no ads, no analytics, no record of where you walked. If a green looks wrong, there is a button on the round screen to tell us, and a person checks the report before anything changes.

That is the whole product. The demo above is not a simplified version of it; it is roughly all of it, minus the walking.

Get it

Yardage is an iPhone app with 14,987 courses in all 50 states mapped and bundled. It's in a free public beta on TestFlight, with unlimited rounds while the beta runs. If you are on a desktop, the download page has a code to scan, and the home page has the rest of the story in about the time it takes to read a scorecard.