Free, science-backed calculators and converters for hikers, climbers, and outdoor athletes. Every tool is built on a published model — Naismith’s rule, the Pandolf equation, the ASTM R-value standard, and recognised grade tables — and runs entirely in your browser.
No sign-up and no accounts. Where a tool saves your inputs, that data stays on your device. For the terms behind the tools, see the glossary and our comparisons.
Outdoor Measurement Converter
Convert the units that come up outdoors — distance and elevation (km/mi, m/ft), temperature (°C/°F), pack weight (kg/lb), volume (L/gal), speed (km/h/mph), and running pace (min/km ↔ min/mile) — all in one place.
Open tool →Climbing Grade Converter
Convert climbing and bouldering grades across every major system — YDS, French, UIAA, Ewbank, and British trad for routes, plus the V-scale and Fontainebleau (Font) scales for bouldering — using recognised conversion tables.
Open tool →Hiking Calorie Calculator
Estimate the calories you’ll burn on a hike from your body weight, pack load, distance, pace, and grade, using the Pandolf load-carriage equation from exercise physiology.
Open tool →Hiking Pace & Time Calculator
Predict how long a hike will take from its distance and elevation gain, using Naismith’s rule with Langmuir corrections for steep ground and fatigue.
Open tool →Pack Base Weight Calculator
Build a full gear list, total your pack’s base weight, and see where you land on the ultralight-to-traditional spectrum. Your list saves privately in your own browser.
Open tool →Sleeping Pad R-Value Calculator
Add up the R-values of stacked sleeping pads and check whether your sleep system matches the conditions you’re heading into, using the ASTM F3340 R-value standard.
Open tool →What these tools do
Each Trailpedia tool turns a question outdoor athletes actually ask — how long will this hike take, how warm is my sleeping setup, what is this grade in my system — into a quick, reliable answer, using a recognised model rather than guesswork. Here is what each one is and the science it runs on.
Outdoor measurement converter
The outdoors is stubbornly bilingual about units: US maps and guidebooks use feet, miles, and Fahrenheit, while most of the world uses meters, kilometers, and Celsius — and gear is often labelled differently again. This converter handles all the everyday ones in one place: distance and elevation (km, mi, m, ft, yd), temperature (°C/°F), pack weight (kg, lb, g, oz), volume for water and fuel (L, gal), speed (km/h, mph), and running pace (min/km ↔ min/mile, entered as mm:ss). It also lists the quick mental-math shortcuts — km ≈ miles × 1.6, meters ≈ feet ÷ 3.3, °F ≈ °C × 2 + 30 — so you can estimate on the trail. Open the measurement converter →
Climbing grade converter
Climbing difficulty is rated on a scale, but almost every country uses a different one — so a route or boulder problem can carry several different-looking grades. This converter translates a grade between the major systems: the YDS (US routes), French sport, UIAA, British trad (adjectival + technical), and Ewbank (Australia/NZ) for roped climbing, plus the V-scale and Fontainebleau (Font) scales for bouldering. Enter a grade in the system you know and read off the equivalents — useful when travelling, reading a foreign guidebook, or comparing your projects. It is built on widely used conversion tables; grade equivalences are approximate by nature, so treat boundaries between systems as a guide, not gospel. Open the grade converter →
Hiking calorie calculator
This estimates how much energy you will burn on a hike so you can plan food and fuelling. It uses the Pandolf equation, a metabolic-cost formula developed for load-carriage research that accounts for your body weight, pack weight, walking speed, the terrain underfoot, and the slope of the ground. Heavier loads, faster paces, rougher ground, and steeper climbs all raise the number. Enter your details to see calories burned per hour and for the whole hike — handy for working out how much to eat on a big day. Like all such formulas it is an estimate; individual metabolism and efficiency vary. Open the calorie calculator →
Hiking pace & time calculator
This predicts how long a hike will take from its distance and elevation gain — the key to planning turnaround times and getting back before dark. It uses Naismith’s rule (roughly an hour for every 5 km, plus an hour for every 600 m of ascent) refined with Langmuir corrections, which add time for steep descents and ease it on gentle ones. Enter your route’s distance and climb to get an estimated time, then adjust for your own fitness, pack, and rest stops. Open the pace & time calculator →
Pack base weight calculator
Base weight is the weight of your pack and all your gear excluding consumables — food, water, and fuel — and what you wear. It is the standard figure backpackers use to compare setups and chase a lighter load, because it stays constant while consumables come and go. Build a categorised gear list and the tool totals your base weight and shows where you sit on the spectrum, from traditional through lightweight to ultralight and super-ultralight. Your list saves privately in your own browser, so you can refine it over time. Open the base weight calculator →
Sleeping pad R-value calculator
A sleeping pad’s R-value measures how well it resists heat loss into the cold ground — the higher the number, the warmer the pad — and the ASTM F3340 standard finally made R-values comparable across brands. A crucial detail: when you stack two pads, their R-values add together. This tool sums the R-values of stacked pads and tells you whether your total is enough for the temperatures you are heading into, since insulation from the ground matters as much as your sleeping bag when it is cold. Open the R-value calculator →
Built on published science
Every calculator above uses an established, published model — Naismith’s rule, the Pandolf equation, the ASTM R-value standard, and recognised grade tables — and shows its assumptions so you can see how a result is reached. They run entirely in your browser, with no sign-up; where a tool stores your inputs, that data stays on your device. Because they are models, the outputs are planning estimates, not guarantees: real-world results vary with fitness, conditions, gear, and many other factors, so always keep a margin of safety. Read more in our editorial guidelines and disclaimer.