Free Trail Running Tools - Trailia

Every tool here is free to use. The calculators return their complete result with no account at all. Two planning tools give a free preview with the full document behind a free account. Nothing on this page requires a paid subscription.

Instant Calculators

Answers computed in your browser as you type. Nothing uploaded, nothing stored, no usage limits.

Sweat Rate & Hydration Calculator for Trail Running

Measure your sweat rate from a before and after weigh-in, or estimate it from the conditions, then see how much water to carry on any trail run.

  • Measured sweat rate from your weight before and after a run, fluid drunk and run time
  • Sweat-rate estimate from temperature, humidity, effort, body weight and vertical density
  • Drinking range in ml per hour and total fluid to carry
  • Sodium target in mg per hour
  • Complete result, no account required
  • Link: https://trailia.run/tools/hydration-calculator

Carbs Per Hour Calculator for Trail Running & Ultras

Carbs per hour, total carbs, calories and gels for any trail run or ultra.

  • Carbohydrate band by duration, capped by gut training
  • Energy cost of the route including climbing and descending
  • Gel, bar and drink mix equivalents, plus caffeine dosing
  • Complete result, no account required
  • Link: https://trailia.run/tools/fueling-calculator

Trail Pace Calculator

Convert a road pace into a realistic trail pace for any elevation profile.

  • Strava-aligned grade-adjusted pace model
  • Trail pace, finish time, climb pace and descent pace
  • Grade-adjusted pace table for every gradient
  • Complete result, no account required
  • Link: https://trailia.run/tools/pace-calculator

ITRA Km-Effort Calculator

Km-effort, ITRA distance category and an indicative performance band.

  • Official ITRA km-effort formula (distance + gain/100)
  • XXS to XXL category classification
  • Indicative performance band — not an official ITRA Performance Index
  • Complete result, no account required
  • Link: https://trailia.run/tools/itra-index-calculator

Planning Tools

Race Pacing & Cutoff Planner

Turn a goal finish time into a segment-by-segment pacing sheet.

  • Free without an account: course summary, required average pace, and the first three segments
  • With a free account: the complete split table, cutoff cushion analysis and per-segment fuelling
  • Run, hike and controlled-descent calls per segment
  • Link: https://trailia.run/tools/pacing-planner

Trail Training Plan Generator

A periodized training plan for any trail distance, from 10K to 100K ultra.

  • Free without an account: plan structure, phases and key workouts
  • With a free account: full session detail, pace zones and adaptive adjustments
  • Terrain and elevation-aware, calibrates to Strava and Garmin data
  • Link: https://trailia.run/tools/training-plan-generator

AI Analysis Tools

Complete result without an account, limited to a few runs per hour per IP because each one calls an AI model.

Trail Race Time Predictor

Upload your race GPX and a recent result to get an AI-powered finish time prediction.

Race Report Generator

Upload your FIT + GPX files from a completed race for a detailed post-race analysis.

Race Readiness Score

Find out if you're ready for your next trail race.

Trail Finder

Discover trail running routes near any location.

FAQ

Are these tools really free? Yes. The calculators return their complete result with no account. The two planning tools give a free preview with the full document behind a free account. No paid subscription is required for any tool.

Which tools work without an account? The hydration, fuelling, pace and km-effort calculators return their full result instantly. The race predictor, race report, readiness score and trail finder also work anonymously, limited to a few runs per hour. The pacing planner and training plan generator need a free account for the full breakdown.

Why do some tools ask me to sign in for the full result? Because their output is a multi-page document rather than a number. Those gates are enforced on our servers, not hidden in the page.

How much water should I carry on a trail run? Most trail runners need 400-800 ml per hour depending on heat, humidity, effort and body weight.

How many carbs per hour should I eat in an ultra? 60-90 g per hour beyond about two and a half hours if your gut is trained for it; 30-60 g per hour for shorter efforts.

Can I use these tools if I already have a Trailia account? Yes. They are linked from the app navigation under Tools, and signed-in athletes get the full result on every tool.

Is my data stored? No. The calculators run entirely in your browser. The AI tools process your GPX and race data in memory and never save it.

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