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Running & Track

For runners — road, track, or trail. Pace calculator converts between min/mi, min/km, and total time. Heart rate zones from age give you Zone 2 / threshold targets. Tabata / interval timer for track repeats. Plus the rest of the fitness stack — calories, water, recovery — that running depends on.

9 tools · 4 sections

Pace + splits

3 tools

Min/mi or min/km, race-pace projections, lap splits.

Running Pace Calculator

Calculate running pace, finish time, or distance. Race time predictions and splits.

Precise stopwatch with lap tracking.

Countdown Timer

Set a countdown timer with custom duration.

Intervals + workouts

1 tools

400m repeats, 1k threshold runs, Yasso 800s.

Focus timer with work sessions and break intervals.

Heart rate zones

1 tools

Z2 base, threshold, VO2 max — from your age + resting HR.

Heart Rate Zones

Calculate your training heart rate zones.

Diet + recovery

4 tools

Pre-run carbs, post-run protein, hydration, sleep.

Calorie Calculator

Calculate daily calorie needs based on your goals and activity.

Macro Calculator

Calculate your daily protein, carbs, and fat targets.

Water Intake Calculator

Find out how much water you should drink daily.

Sleep Cycle Calculator

Calculate the best time to wake up or go to bed based on 90-minute sleep cycles.

Looking for something specific? Browse all 240 tools.

Built browser-first. Run by one developer.

Every tool runs on your device. No tracking pixels, no sign-up to start. The numbers below are pulled live from the registry.

240

Free tools

Across 14 categories

7

Visual editors

PDF · image · video · audio

32

Curated kits

By profession + lifestyle

17

AI tools

Powered by Claude API

Files never uploadNo tracking pixelsNo sign-up neededWorks in any modern browser

The handful of AI tools (paraphrase, summarise, blog, captions, etc.) send your prompt text to Anthropic's Claude API to do the work. Files, images, PDFs and video never leave your device. Pick the tools that fit your privacy comfort.