Skip to main content
Calcimator

Brick Workout Calculator

Plan bike-to-run brick workouts with duration, intensity, and pacing targets by race distance and training phase.

About this calculator

A "brick" is any workout that stacks a bike ride directly onto a run with no rest between them, and it's the one triathlon-specific skill you cannot train any other way: the first few minutes off the bike feel like running on stilts because cycling and running recruit your quadriceps and hip flexors in almost opposite firing patterns. This calculator sizes that workout for you. It starts from race-distance duration bands — Sprint tops out around 50 minutes of bike and 20 of run, Ironman ranges up to 300 minutes of bike and 60 of run — then slides your session toward the shorter or longer end of that band using a periodization factor keyed to weeks until race day: base phase (more than 8 weeks out) and taper (1 week or less) stay short, while the build and peak windows push toward the longer end.

Bike intensity is set from your FTP at 82% for Sprint/Olympic or 73% for 70.3/Ironman, reflecting that shorter races are raced harder. The headline number to watch is the run-pace slowdown: your standalone easy pace is degraded by 8-15% (bigger degradation further from race day, when the goal is simply teaching the legs to transition, not rehearsing race pace), which is what your brick run should feel like — if you're hitting standalone pace off the bike, you went too easy on the bike leg. Calorie, distance, and bike-speed figures here are rough planning estimates, not physiological measurements, so use them for fueling logistics rather than as a training-load metric.

Inputs

Results

Total workout (min)

89

Bike duration (min)66
Run duration (min)23
Bike intensity (% FTP)82
Bike target (watts)164
Brick run pace (min/km)6.32
Pace slowdown (%)15
Bike distance (km)33
Run distance (km)3.64
Calories burned870
Bricks per week2
T2 practice (sec)120
How to Use This Calculator
  1. Select your Race Distance (Sprint, Olympic, 70.3, or Ironman).
  2. Enter Weeks Until Race and your Easy Run Pace in min/km.
  3. Optionally set your Bike FTP in watts for power-based targets.
  4. Review Total Workout Time, Bike Duration, Run Duration, and Bike Target Watts.
  5. Use Brick Run Pace, Estimated Calories, and Recommended Bricks per Week to structure your training week.

What each input means

Race Distance
Target race distance determines workout duration ranges.
Weeks until race
Weeks remaining until your A-race. Affects workout volume and intensity.
Easy run pace (min/km)
Your comfortable standalone easy run pace in minutes per kilometer.
Bike FTP (watts)
Functional Threshold Power on the bike. Set to 0 if unknown.

What each result means

Total workout (min)
Combined bike and run duration for this brick workout.
Bike duration (min)
Recommended bike leg duration.
Run duration (min)
Recommended run leg duration off the bike.
Bike intensity (% FTP)
Target bike intensity as percentage of FTP.
Bike target (watts)
Target average watts for the bike leg.
Brick run pace (min/km)
Expected run pace off the bike (slower than standalone).
Pace slowdown (%)
Percentage slower than your standalone easy pace.
Bike distance (km)
Estimated bike distance covered.
Run distance (km)
Estimated run distance covered.
Calories burned
Approximate total calories burned during the brick.
Bricks per week
Recommended number of brick workouts per week at this training phase.
T2 practice (sec)
Target transition time to practice between bike and run.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Race Distance = 2, Weeks until race = 12, Easy run pace (min/km) = 5.5, Bike FTP (watts) = 200 = 4 input(s) provided
  2. Calculate Total workout
    Total workout = bikeDurationMin + runDurationMin
    89 = 89
  3. Calculate Bike duration
    Bike duration = round(bikeRange.min + (bikeRange.max - bikeRange.min) * periodFactor)
    66 = 66
  4. Calculate Run duration
    Run duration = round(runRange.min + (runRange.max - runRange.min) * periodFactor)
    23 = 23

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.

Frequently Asked Questions

Why does my run pace get worse the further out I am from race day, instead of better?

The pace slowdown applied is deliberately larger early in your training block: 15% when you're more than 8 weeks out, 10% during build/peak, and just 8% inside the final 3 weeks. Early in a season the point of a brick is simply teaching your legs to run at all after cycling, not rehearsing race pace — the calculator tightens the slowdown as race day gets closer and pacing accuracy starts to matter more.

Why is bike intensity set to 82% FTP for Sprint/Olympic but only 73% for 70.3/Ironman?

The calculator ties bike intensity to how hard you'll actually race that distance. Sprint and Olympic are raced close to threshold, so their brick rides load your legs near that same intensity. 70.3 and Ironman are long, pacing-disciplined efforts held well below threshold, so their bricks target a more moderate 73% of FTP to mimic sustainable race effort rather than pre-fatiguing your legs before the run.

How does the periodization factor change my workout's duration as race day approaches?

Four factors drive it: 0.4 in base phase (more than 8 weeks out), 0.75 in build (4-8 weeks), 0.6 in peak (2-3 weeks), and 0.25 in taper (1 week or less), each multiplied against your race distance's bike/run duration range. Base and taper produce short bricks focused on skill and frequency, while the build phase generates the longest bricks in your whole plan.

Are the calorie and distance estimates precise enough to plan race-day fueling around?

No — they're rough planning figures built on flat per-minute burn rates (9 cal/min biking, 12 cal/min running) and simplified average speeds (30 km/h for Sprint/Olympic, 28 km/h for 70.3/Ironman), not a measurement of your actual output. Use them to get a ballpark sense of workout load and fueling logistics, but calibrate against your own heart rate, power, or perceived effort for anything more precise.

Related Calculators

The questions that sit next to this one — chosen by subject, including calculators filed under a different category.

Adventure Racing

Multi-Sport Transition Calculator

Transition planning for adventure racing (paddle/bike/run).

Triathlon

Triathlon Pacing Calculator

Calculate split times for swim, T1, bike, T2, and run from your target finish time across sprint, Olympic, 70.3, and Ironman distances.

Triathlon

Sprint Triathlon Training Plan Calculator

Weekly training hours by discipline for sprint distance (750m swim, 20km bike, 5km run) with periodization phases.

Triathlon

Transition Practice Planner Calculator

Plan T1 and T2 transition practice with projected time savings and drill recommendations.

Earthen Building

Adobe Brick Calculator

Brick count from wall dimensions and brick size.

More in Sports, Outdoors & Recreation.