Tools and calculators

A calculator is only as good as the method behind it. That is why ours never stand alone: each one sits inside a guide that says where its formulas come from (a standard, an official scale, a manufacturer’s data or a public service) and where its results stop being reliable. Units follow your edition, and nothing you type ever leaves your browser.

The list grows as new guides are published.

• Hiking

  Work out your walking time

  Enter the distance, ascent and descent of your route: the three methods in the table are worked out straight away.

  In the guide: Walking time on a hike: how to estimate it without getting it wrong

• Campervans

  Work out your battery capacity

  Take the total of your daily energy budget, in watt-hours, and the number of days the battery must last without charging.

  In the guide: Leisure battery: how to work out the capacity your campervan needs

• Campervans

  Work out your panel’s output

  Choose the wattage of your flat-mounted panel, your daily consumption, the city closest to where you travel and the month: you get the average output per day and the wattage that would cover your consumption.

  In the guide: Campervan solar panels: how many watts to fit for each season

• Trail running

  Work out a race’s km-effort

  Enter the distance and ascent given by the organiser.

  In the guide: Km-effort in trail running: the calculation, ITRA points and their limits

• Snow

  Work out the feels-like temperature

  Enter the air temperature and wind speed from the forecast: you get the feels-like temperature and the frostbite risk for exposed skin.

  In the guide: Dressing for the cold: the three-layer system explained

• Snow

  Work out your pole length

  Enter your height: both lengths use Salomon’s ratios, as in the table.

  In the guide: Cross-country skiing: classic or skating, and how to choose as a beginner

• Sea

  Work out your board volume

  Enter your weight and level: the volume comes from Firewire’s table, interpolated between its rows.

  In the guide: Surfboard volume: how to work it out from your weight and ability