---
title: "Hiking Time Calculator: Naismith & Tobler | Summit Cabin"
description: "Estimate walking time for a hill route with Naismith's rule and Langmuir's corrections, and with Tobler's hiking function. Metric, imperial or GPX."
url: https://summitcabin.top/
---

# Hiking time calculator

Two classic rules for how long a hill walk takes, worked out side by side: Naismith's rule with Langmuir's corrections, and Tobler's hiking function. Type the distance and climb, or drop in a GPX file.

## How the two rules work

**Naismith's rule** comes from an 1892 trip report by the Scottish climber William Naismith: allow an hour for every three miles on the map, plus an hour for every 2,000 feet of ascent. The metric version is 5 km/h plus an hour per 600 m. Eric Langmuir later added corrections for descent: take off 10 minutes per 300 m on gentle slopes (5° to 12°) and add 10 minutes per 300 m on steeper ones.

**Tobler's hiking function** (1993) turns slope into speed: *W* = 6 e−3.5 |S + 0.05| km/h, where *S* is the rise over the run. That gives about 5 km/h on the level and a top speed of 6 km/h on a slight descent of 5%. Off paths, Tobler multiplies the speed by 3/5.

## Why they disagree

Naismith charges a fixed hour for every 600 m of climb, however steep. Tobler's speed falls away smoothly with steepness, so it is brisker than Naismith on moderate climbs and much slower on very steep ground. Downhill, Tobler slows on steep slopes, while Langmuir's gentle-descent credit can imply very fast walking near 12°. Where the two differ a lot, plan on the longer time. Both give moving time for a fit walker in good conditions.

## Typed totals or a GPX file

With typed totals we assume one even climb and one even descent at the route's average grade. A GPX file is better: we smooth its heights over about 100 m, so GPS jitter does not inflate the ascent, and judge every short step on its own slope. Your level-ground speed scales both rules.

## Sources

- Naismith WW. Excursions: Cruach Ardran, Stobinian, and Ben More. *Scottish Mountaineering Club Journal* 1892;2(3):136.
- Langmuir E. *Mountaincraft and Leadership*. Edinburgh: Scottish Sports Council, 1984. Corrections summarised in [How to calculate route times using Naismith's rule](https://www.ukhillwalking.com/articles/skills/how_to_calculate_route_times_using_naismiths_rule-7777), UKHillwalking.
- Tobler W. Three presentations on geographical analysis and modeling. *NCGIA Technical Report* 93-1, 1993: the hiking function is figure II. [Archived PDF](https://web.archive.org/web/20080422231635/http://www.ncgia.ucsb.edu/Publications/Tech_Reports/93/93-1.PDF).
- Scarf P. Route choice in mountain navigation, Naismith's rule, and the equivalence of distance and climb. *Journal of Sports Sciences* 2007;25(6):719–726. [doi:10.1080/02640410600874906](https://doi.org/10.1080/02640410600874906)

## More trail tools

Each tool has its own page and keeps working offline once loaded.

- [Elevation gain & grade calculator](https://summitcabin.top/elevation-gain-grade/): Percent grade, degrees and ratio for a stretch of trail, or a whole GPX track.
- [Pack weight calculator](https://summitcabin.top/pack-weight-calculator/): Your loaded pack as a share of body weight, with an optional gear list.
- [Hiking water calculator](https://summitcabin.top/hiking-water-calculator/): A transparent estimate of how much water to drink and carry.
- [Trail day planner](https://summitcabin.top/trail-day-planner/): Start time, breaks, turnaround and sunset in one printable plan.

## Recommended

Two free tools from outside the hills that help with the online side of planning a trip.

### Keep download forms out of your inbox

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[Open a temporary inbox](https://cleantempmail.com/)

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[Look up a shop with WebTraceCheck](https://webtracecheck.com/)

## Questions

**Which estimate should I trust?**

Neither exactly. Compare them with your own past walks. On unfamiliar or steep ground, plan on the longer one and add time for stops, weather and the slowest walker.

**Why is the ascent from my GPS app different?**

Apps smooth elevation in different ways, and raw GPS heights jitter up and down. Counting every small wiggle as climbing inflates the total, so two apps can report quite different figures for the same track.

**How do I set my own pace?**

Time yourself on a level walk you know and enter that speed. If your GPX file has timestamps, we also show the recorded time so you can compare it with both rules.