Hiking Turnaround Time Calculator

1. Enter the hours of daylight left when you set off.
2. Enter your estimate of the time to reach the goal, one way.
3. Set a safety buffer to keep back for delays and dusk.
4. Read the latest time after starting by which you must turn around.

A turnaround time is a pre-agreed moment when you stop going forward and head back, whether or not you have reached your goal. It is one of the most important safety habits in the hills, because it removes the temptation to push on when the summit is tantalisingly close but the daylight is running out.

Most accidents on big days happen on the descent, in the dark, when people are tired. Setting a turnaround time before you start, and sticking to it, keeps the return within daylight and within your reserves.

1. Subtract your safety buffer from the daylight for the usable time.
2. Assume the return takes about the same time as the outbound leg.
3. Subtract the outbound time from the usable time for the latest turnaround.
4. If that is less than the time to the goal, you cannot reach it safely.

The logic is simple but strict: whatever you have not reached by the turnaround time, you leave for another day.

You start with 8 hours of daylight, keep a 1 hour buffer, and estimate 3 hours to the summit. Your usable time is 7 hours. The latest turnaround is 7 minus 3, which is 4 hours after starting. Since the return also takes about 3 hours, reaching the summit at the 3 hour mark leaves 1 hour of spare time, so the goal is achievable. If the summit were 4 hours away, the turnaround would fall before you arrived, and you would turn back short.

Daylight Available

Short winter days slash the usable window, so the same route needs a much earlier turnaround than in summer.

Your Buffer

A bigger safety buffer pulls the turnaround earlier but protects against delays, navigation and slow descents.

Speed and Conditions

If the ground or weather slows you, your time to the goal grows and the turnaround moves earlier.

Return Being Slower

Tired legs and fading light can make the descent slower than the climb, so err on the side of caution.

The same 3 hour goal needs very different turnarounds by season.

In deep winter a late start can leave almost no window at all, which is why alpine starts matter so much.

Before a Big Day

Fix a turnaround time in advance so the decision is made when you are calm, not tired.

Short Winter Days

Check that an ambitious objective actually fits the limited daylight.

Group Trips

Agree a shared turnaround so no one feels pressure to push on alone.

1. No Buffer

Planning to finish exactly at sunset leaves nothing for delays; always keep a buffer.

2. Ignoring the Descent

The return can be as slow as the climb, so budget the full round trip.

3. Summit Fever

Pushing past the turnaround because the goal looks close is how people get caught out in the dark.

4. Forgetting Winter Light

Daylight is short and dusk comes fast in winter; check sunset, not just the clock.

The turnaround maths is exact for the figures you enter. Its value depends on an honest estimate of your time to the goal and the daylight you have.

Subtract your safety buffer from the daylight for usable time, then subtract your one-way time to the goal. With 8 hours of light, a 1 hour buffer and a 3 hour goal, turn around 4 hours after starting.

A pre-agreed moment when you head back whether or not you reached your goal, so the descent finishes safely within daylight.

Most trouble happens on tired descents in the dark. A fixed turnaround removes the pressure to push on when daylight is running out.

At least an hour for most days, more in winter, on hard ground, or with a group, to cover delays and a slower descent.

Yes. Tired legs and fading light can make the descent slower than the climb, so keep a generous buffer.

Turn back at the turnaround time regardless. The summit will still be there another day; getting caught in the dark is the real risk.

It uses the daylight hours you enter. Check the real sunset for your date and location, and set your daylight figure from that.

The simple version assumes the return equals the outbound. For a loop, estimate the remaining time to finish instead of doubling the outbound.

No. The calculator runs entirely in your browser and nothing you enter is stored or sent anywhere.

• Hiking safety (Wikipedia).
• Mountaineering and turnaround times (Wikipedia).
• Twilight and daylight (Wikipedia).