Train with Pace & Purpose

Free tools for runners and CrossFit athletes — calculate your pace, find your zone 2 heart rate, and generate daily workouts.

Tools

⏱️

Pace Calculator

Convert finish times to pace per km or mile. Get split times for any distance from 1K to marathon.

Calculate pace →
📊

Pace Chart

Half and full marathon pace reference tables. Look up the pace you need for any target finish time.

View chart →
🎯

Race Predictor

Predict finish times at other distances based on a recent race result using the Riegel formula.

Predict time →
🫀

Heart Rate Zones

All five training zones from recovery to VO2 max. Max HR, Karvonen, or LTHR methods for runners.

View zones →
🔬

VO2 Max & VDOT Calculator

Estimate aerobic capacity (VO2 max) and running performance (VDOT) from a race or Cooper test.

Estimate VO2 max & VDOT →
🔥

Running Calories

Calculate calories burned based on weight, distance, and pace using MET values.

Calculate calories →
💓

Zone 2 Calculator

Find your aerobic base heart rate zone using age-based or Karvonen formulas. Build endurance the right way.

Find your zone →
🏋️

WOD Generator

Generate random AMRAP, EMOM, For Time, and Chipper workouts with your available equipment.

Generate WOD →

Why PaceWOD

Most fitness sites give you a calculator and a paragraph of generic advice. PaceWOD is built for athletes who already train with data — Garmin lap splits, COROS training load, Apple Watch HR drift — and need to know which number to trust when they conflict.

Every guide on this site follows the same decision framework: name the method (Riegel, Karvonen, Daniels VDOT, MET), show where wearables introduce error, then give a concrete training action. A race predictor that says 1:42 half marathon means nothing if your last 10K was on a net-downhill course in cool weather — we explain when to adjust the input and when to ignore the output.

What Makes Our Content Different

  • Tested workouts, not random lists — CrossFit WODs in our library include documented scores, pacing mistakes, and scaling notes from real sessions
  • Device-aware analysis — Articles compare wrist HR vs chest strap, Garmin Firstbeat VO2 vs lab values, and watch calorie estimates vs MET math
  • Honest limits — Training plans state what a formula cannot predict (heat, fueling, course profile, cardiac drift)
  • No account required — All tools run in your browser; your training numbers never leave your device

Who This Is For

Recreational runners building toward a first 5K or a sub-2 half marathon. CrossFit athletes who want conditioning benchmarks beyond the daily whiteboard. Anyone frustrated when "easy pace" on the watch feels impossible on a humid Tuesday — and wants a physiological explanation, not a motivational quote.

PaceWOD is operated independently by an endurance athlete with an engineering background. Read our About page for editorial standards, Privacy Policy for how we handle data, or contact us to report an error in a guide or calculator.

Performance Guides

Data-driven articles on running science, heart rate training, and wearable analytics — written for athletes who use Garmin, COROS, and pace data.

Heart Rate

Zone 2 vs Zone 3 Running

Why easy days drift into gray zone — and how LTHR-based zones differ from Garmin defaults.

Read analysis →
Running Science

How to Improve VO2 Max

When watch VO2 lags race fitness, and which interval formats actually move the number.

Read analysis →
Energy

How Many Calories Does Running Burn?

MET estimates vs Garmin calories — why distance and weight matter more than pace.

Read analysis →
Race

Race Day Pacing Strategy

Negative splits and checkpoint pacing for 5K through half marathon — with worked split tables.

Read analysis →
Physiology

Heart Rate Drift and Decoupling

What pace:HR decoupling means on long runs — and when >5% signals under-fueling or heat stress.

Read analysis →
Wearables

Apple Watch vs Garmin for Running

GPS, wrist HR, and training metrics — when Apple Watch is enough and when to switch.

Read analysis →
Race

Marathon Pacing Strategy

Even splits, fueling checkpoints, and second-half physiology with a sub-4 worked example.

Read analysis →
Training

Polarized Training (80/20)

Seiler research with sample weeks at 30, 50, and 70 km — and why gray zone kills the model.

Read analysis →
Wearables

COROS vs Garmin for Runners

EvoLab vs Training Status, GPS, battery life — which watch fits your training data needs.

Read analysis →
Race

10K Race Strategy and Pacing

First 5K discipline, km checkpoints for 40–55 min, and when to surge in the second half.

Read analysis →
CrossFit

For Time Workouts Guide

Break strategy, time caps, and scaled templates for sustainable For Time pacing.

Read analysis →
Scaling

How to Scale CrossFit Workouts

Load %, volume cuts, and skill substitutions — when Rx hurts the intended stimulus.

Read analysis →
Engine

Building Engine for CrossFit

Aerobic base and interval formats — when engine, not strength, limits metcon scores.

Read analysis →
Open

CrossFit Open Strategy

Unknown workout pacing, heat strategy, and fatigue management across Open weeks.

Read analysis →
Calories

CrossFit Calorie Burn Guide

Metcon calorie estimates vs watch data — and why EPOC afterburn is oversold.

Read analysis →
Diet

Running vs CrossFit for Weight Loss

Weekly calorie math, muscle retention, and a hybrid structure that actually moves the scale.

Read analysis →
Wearables

Watch Calorie Accuracy

Why Garmin, COROS, and Apple Watch overestimate burn — use MET math instead.

Read analysis →
Sleep

HRV for Runners

What your watch measures — and when a low HRV means skip the hard session.

Read analysis →
Race

Pre-Race Sleep Strategy

Two nights before matters more than race eve — anxiety, travel, and caffeine rules.

Read analysis →
CrossFit

Evening Workouts and Sleep

How late is too late for metcons — intensity cutoffs that protect next-day performance.

Read analysis →
Speed

Strides and Pickups

Add speed after easy runs without stacking fatigue — short form-focused reps.

Read analysis →
Garmin

Garmin Body Battery Guide

What the score measures — and when to ignore it before a quality session.

Read analysis →
CrossFit

Assault / Echo Bike Pacing

Calories and RPM strategy so bike stations don’t wreck the rest of the WOD.

Read analysis →

Browse all guides by topic →