4sum keeps score for your group's side games and works out who pays who at the end.

No more napkin maths on the tailgate.

TWENTY GAMES, NOT FIVE
Wolf, Nassau with presses, Skins with carryovers, Vegas, Banker, Bingo Bango Bongo, Snake, Sixes, Rabbit, Dots and junk, Left-Right, Scotch, High-Low, Niner, Match Play, Best Ball, Stableford, Stroke, Scramble and Longest Drive. Run as many at once as you like on the same card.

IT TEACHES THEM TOO
Every game has a how-to and a worked example, because the hardest moment in a side game is the tee box where somebody says "wait, how does this one work?" Nobody else explains them. We do.

IT SETTLES UP
At the end, every game is netted across every player and reduced to the fewest possible payments. Not a table of who owes what to whom eleven times over, just "Mike pays Pat $45."

4sum is a scorekeeper. It does not process payments, take a cut, or hold anybody's money — the app only does the arithmetic, and your group settles between yourselves however you already do.

IT TELLS YOU WHAT THE HOLE IS WORTH
A strategy helper works out what is actually on the line before you hit, from the real state of every game you have running. It cannot disagree with the scoring, because it reads the same numbers.

FIND YOUR COURSE
Search by name or town and add a course with one tap, scorecard, tees, ratings and slope included. Some courses are on the map but have never been named by anyone — 4sum shows those too, so you can set one up once and keep it. Add your own if it is not there at all.

GPS DISTANCES
Front, middle and back of the green, live as you walk. Tap Find on map and 4sum pulls the greens from OpenStreetMap where they have been mapped, or stand on a green once and mark it yourself. Tap anywhere on the hole for the carry and what is left from there. Mark your own bunkers and layup targets once and they read out on every round after.

LONGEST DRIVE, MEASURED
Mark the tee, hit, mark the ball. Add the game whenever you feel like it and use it on whichever holes you want.

LIFETIME RECORDS
Every finished round adds up: lifetime totals, rounds won, and a head-to-head record against everyone you play with.

FREE, AND IT STAYS THAT WAY
No account. No ads. No subscription. Nothing to sign up for. Your rounds live on your phone and work with no signal, which is what you want on the back nine anyway.

LOCATION
4sum uses your location only while you have the app open, to measure how far you hit it and how far you have left to the green. It is never collected in the background, and it stays on your phone unless you switch on shared course maps, which send the greens and tees you mark and your position on a good GPS fix (never your name or a score) so other players at the same course get them too.

Course data © OpenStreetMap contributors, ODbL 1.0, via OpenGolfAPI (opengolfapi.org), and compiled by Two Beers Studios from published scorecards.