How do you find a midpoint by public transport?

Not by measuring distance. You compare how long each person's journey actually takes on the network, then pick the stop where the times land closest together rather than the one that is merely quickest on average. That is normally a multi-line interchange, and it is often nowhere near the geographic middle.

Why is the geographic midpoint wrong on a metro network?

Because the lines radiate from the centre. Two people a few miles apart can be forty minutes apart if the network sends them in through the middle and back out again, so a point that looks halfway on a map can be the slowest place for everyone to reach.

Does it work if some of the group is not on public transport?

Yes. Travel mode is set per person, so the two people on the metro are timed on the metro while the one who cycles is timed on the road network. Each journey is measured on its own terms and compared in minutes.

Does it account for changes and waiting time?

It uses real door-to-door transit times, which include the walk to the stop, the ride and the changes in between. That is the whole point - a station two stops closer is not fairer if getting there needs an extra change.

Meet halfway by public transport

On a public transport network the fairest meeting point is usually the station the most lines pass through, not the one nearest the middle of the map - metro and rail lines radiate from the centre, so travel time follows the network rather than the distance. togather times each person's real door-to-door journey and returns the stops that keep the trip even.

Find your meeting point How it works

Why distance is the wrong unit on a transit network

A meeting point is fair when everyone spends roughly the same time getting there. On a road that is nearly the same thing as distance. On a metro network it is not even close, because the network decides the route and most networks are built to move people in and out of the centre rather than around the edge.

The practical effect is that travel time follows the lines. Two people three miles apart on different branches can be forty minutes apart, while two people eight miles apart on the same line are twenty minutes apart. Any tool that averages coordinates and drops a pin is answering a question about geometry when the group asked a question about time.

What actually makes a stop fair

Two things, and neither is visible on a map of the city.

How many lines touch it. A single-line station is only fair to the people already on that line. An interchange is reachable without doubling back from far more of the city, which is why the same handful of stations keep winning in every city guide on this site.
Which districts feed into it without a change. A change costs the walk between platforms plus the wait, and it is the thing that turns a short-looking journey into a long one.

Read the spread, not the average

The number worth optimising is the spread - the gap between the longest and the shortest journey in the group. An average hides the person carrying the trip, and that person is the one who decides whether the plan happens at all. togather shows each person’s time alongside the result for exactly that reason: a spot that is ten minutes for three people and fifty for a fourth is not a compromise, it is a fifty-minute journey with extra steps.

Add everyone’s starting point, set how each person travels, and send the result straight to the group chat.

How togather works it out

Add everyone's starting point
Enter up to six starting points - a street, a station or a neighbourhood is enough. Nobody has to share a precise address with the group.
Set each person to their own mode
Public transport for the people on the metro or the train, and a different mode for anyone cycling, walking or driving in. Mixed groups are the normal case, not an edge case.
Read the spread, not just the midpoint
togather shows every person's travel time next to the result, so the group can see the gap between the longest and the shortest journey rather than taking the answer on trust.

Worked through, city by city

These guides name the interchanges that actually work as a fair midpoint in each city, and why the geographic middle tends to be the wrong answer there.

Questions

How do you find a midpoint by public transport?: Not by measuring distance. You compare how long each person's journey actually takes on the network, then pick the stop where the times land closest together rather than the one that is merely quickest on average. That is normally a multi-line interchange, and it is often nowhere near the geographic middle.
Why is the geographic midpoint wrong on a metro network?: Because the lines radiate from the centre. Two people a few miles apart can be forty minutes apart if the network sends them in through the middle and back out again, so a point that looks halfway on a map can be the slowest place for everyone to reach.
Does it work if some of the group is not on public transport?: Yes. Travel mode is set per person, so the two people on the metro are timed on the metro while the one who cycles is timed on the road network. Each journey is measured on its own terms and compared in minutes.
Does it account for changes and waiting time?: It uses real door-to-door transit times, which include the walk to the stop, the ride and the changes in between. That is the whole point - a station two stops closer is not fairer if getting there needs an extra change.

Also worth reading

Settle it in about a minute

Add everyone’s starting point, pick how each person travels, and send the result to the group. No download, no sign-up.

Find your meeting point