Turnaround Time Calculator

What is a turnaround time in hiking?

A turnaround time is the latest point in your hike where you must reverse direction and head back to the trailhead to return safely before dark. It is calculated by subtracting half the total hiking time and a safety buffer from sunset. Setting a firm turnaround time before leaving and respecting it is the single most important hiking safety practice — most mountain rescues happen because hikers continued past the point of safe return.

How do I calculate the latest safe turnaround time?

The formula is: turnaround time = sunset time − (total hiking time ÷ 2) − safety buffer. For a 6-hour hike with a 17:30 sunset and 60-minute buffer: 17:30 − 3:00 − 1:00 = 13:30. You should be back at the trailhead by approximately 16:30, giving one hour before sunset. This calculator uses regional sunset tables to apply the formula automatically for any month and region.

What safety buffer should I add to my turnaround time?

A minimum 30-minute buffer is suitable for experienced hikers on familiar trails in good conditions. A 60-minute buffer is appropriate for most recreational hiking — it accounts for unexpected delays, wrong turns, and fatigue. A 90-minute buffer is recommended for mountain routes, unfamiliar terrain, groups, or when weather may deteriorate. The buffer also ensures you have sufficient light for route finding and photo stops on the way back.

What is the 50% rule in hiking?

The 50% rule states: if you have not reached the halfway point of your planned route by your turnaround time, you turn around — regardless of how you feel or what you can see ahead. This rule prevents summit fever from overriding the rational decision to turn back. It is especially important on out-and-back routes where the return leg takes as long as the outward leg.

Should I always stick to my turnaround time?

Yes — the turnaround time should be treated as a commitment, not a suggestion. The most common mountain accident scenario involves a hiker who felt strong, continued past the turnaround, reached the summit, and then descended in darkness on unfamiliar terrain. Descending in darkness on rocky or steep ground significantly increases the risk of falls. Tell someone your turnaround time before you leave and honour it.

What happens if I do not have enough daylight for my planned hike?

If the calculator shows insufficient daylight, your options are: start earlier that day, choose a shorter route, or postpone to a day with longer daylight. In autumn and winter, many mountain routes require pre-dawn starts to complete safely. Never attempt a route that the calculator flags as unsafe on the grounds that you are fast or the weather is good — conditions can change rapidly in the mountains.

How do I find sunset time for my hiking location?

This calculator uses regional sunset tables averaged across Northern Europe, Central Europe, Southern Europe, and North America. For precise local sunset times, check a weather app (most show sunrise/sunset for your location) or use a dedicated astronomy app. Sunset time varies significantly by latitude — in summer in Northern Europe, sunset can be after 22:00, while in winter it can be before 16:00.

Should I carry a headlamp even if I plan to return before dark?

Yes, always carry a headlamp. Unexpected delays — injury, navigation error, helping another hiker — can mean returning after dark despite good planning. A headlamp weighs 80–100g and takes up minimal pack space. Most mountain rescue incidents that occur after dark involve hikers who did not carry a light because they planned to be back before sunset. A headlamp is non-negotiable safety equipment on any route over 3 hours.