Its wet, windy and you've a novice with you - can they get up that extra 1500 feet or should you turn back ? Two gentlemen Naismith and Tranter came up with a set of calculations that attempt to answer the question of whether a walk / scramble is achievable by a given party and how long will it take.

Of course no system is infallible but the results are generally fairly accurate. Three key tips to use it more effectively:

1) For the most accurate time results break your journey down into smaller chunks to assess each section.

2) To get a better feel for whether your entire party is up to the planned trip base the results on the least fit / experienced person in your team and use the entire journey as the basis for the calculation.

3) Its also a good idea to try varying the weather and/or terrain data to see how sensitive your plan is to various unpredictable elements such as change of weather or variation of planned route.

http://www.walkhigh.co.uk/acatalog/Naismith_Calculator.html

The calculator is for indicative purposes only, how it actually relates to your team and the conditions on the day is a matter of your personal judgement. Be prepared to change your plans should conditions vary too much from your plan. To improve the accuracy of these results..