Brick Workout Calculator

Updated Sep 2026 Used 0 times

Your result

Bike-to-run brick workout plan

Enter your values, then calculate to see a verified result.

Inputs usedReview the information used for this result.

Full calculation and sourcesOpen Full calculation and sources to audit the formula, assumptions, fixtures, and interpretation limits.

Versioned calculationFormula v1.0.0

Method shown

The selected equation and assumptions stay visible.

Cross-checked

Supporting outputs expose unit and protocol mistakes.

Actionable

The result links to the next relevant planning task.

Step 1Set bike and run durations.90-bike 20-run brick

Step 2Add realistic transition time.90-bike 20-run brick

Step 3Enter relative intensities from your own zone system.90-bike 20-run brick

Interpretation

The load index is a planning convention and does not predict recovery.

Relative bike and run intensity references are sport-specific.

Fuel and fluid tolerance must be practiced; overdrinking and underfueling both carry risks.

Use this result

Check the worked exampleAudit the equation with a concrete case.Interpret the result safelyReview what the result can and cannot establish.

Keep exploring

4 available tools

Training Zones GeneratorBuild a transparent 3-, 5-, or 6-zone table.Fluid Loss CalculatorMeasure condition-specific sweat loss and rate.Carb Loading CalculatorTurn a selected g/kg target into a food-planning quantity.Race Day ChecklistGenerate a race-, weather-, and travel-specific checklist.

Public verification recordFormula v1.0.0

Review scope: Segment Duration, Transition Exclusion From Load/fuel, Weighted Intensity, Squared Load, And Rate Totals.
Review team: CalculatorGeek Expert Review Team
Verified: 2026-09-27
Next source review: 2027-03-27
Automated fixtures: 1 cases

Review method

Recompute Load index = bike hours x bike intensity squared x 100 + run hours x run intensity squared x 100. independently; verify unit normalization, protocol selection, internal consistency, and invalid boundaries.

Known limitations

The load index is a planning convention and does not predict recovery.
Relative bike and run intensity references are sport-specific.
Fuel and fluid tolerance must be practiced; overdrinking and underfueling both carry risks.

Primary sources

Latest update

2026-09-27 · Added complete endurance-suite calculator with verified model, source ledger, premium result, and unified contextual navigation.

Published calculation checks

Case	Inputs	Expected result
90-bike 20-run brick	bike_minutes=90 min, run_minutes=20 min, transition_minutes=2 min, bike_intensity_percent=75 pct, run_intensity_percent=80 pct, carbs_per_hour=60 gph, fluid_ml_per_hour=500 mlph	total_session_minutes=112, active_minutes=110, carbohydrate_grams=110, transparent_load_points=105.7083333333

On this page

Direct answer

The planner combines bike, transition, and run durations, then calculates a transparent duration-by-intensity-squared load index.

Brick workouts develop transition specificity, but the appropriate duration and intensity depend on experience, event demands, and recovery.

Create sport intensity references with the Zones Generator and measure fluid loss with the Fluid Loss Calculator.

How to use the calculator

Set bike and run durations.
Add realistic transition time.
Enter relative intensities from your own zone system.
Enter only fueling and fluid rates you intend to practice.

Inputs, outputs, and result meaning

Inputs

Bike duration: Planned cycling time.
Run duration: Planned run time immediately after cycling.
Transition duration: Time allocated between bike and run.
Bike relative intensity: Percentage of the chosen bike threshold reference.
Run relative intensity: Percentage of the chosen run threshold reference.
Carbohydrate practice rate: A user-selected practiced rate, not a prescription.
Fluid practice rate: A user-selected practiced rate, not automatic sweat replacement.

Outputs

Total session: A displayed result from the stated method and the entered assumptions.
Active time: A displayed result from the stated method and the entered assumptions.
Weighted intensity: A displayed result from the stated method and the entered assumptions.
Transparent load index: A displayed result from the stated method and the entered assumptions.
Carbohydrate assumption: A displayed result from the stated method and the entered assumptions.
Fluid assumption: A displayed result from the stated method and the entered assumptions.
Bike/run time ratio: A displayed result from the stated method and the entered assumptions.

Formula and methodology

Method: Load index = bike hours x bike intensity squared x 100 + run hours x run intensity squared x 100.

This transparent load index is not TSS. Fuel and fluid totals simply multiply entered rates by active time.

Worked examples

90-minute bike plus 20-minute run

With a 2-minute transition, total time is 112 minutes. Fuel and fluid totals are based on 110 active minutes.

Interpretation and limitations

The load index is a planning convention and does not predict recovery.
Relative bike and run intensity references are sport-specific.
Fuel and fluid tolerance must be practiced; overdrinking and underfueling both carry risks.

Frequently asked questions

What is a brick workout?

A multisport session, commonly cycling immediately followed by running.

Is the load index TSS?

No. It is deliberately labeled as a transparent local index.

Should every brick be race intensity?

No. Purpose, experience, phase, and recovery determine intensity.

How should I compare results over time?

Repeat the same protocol, units, equipment setup, and environmental conditions, then review the supporting outputs rather than only the headline number.

Sources and transparency

CalculatorGeek independently recomputed every published fixture on 2026-09-27. Sources establish the equation, protocol, or interpretation boundary; they do not turn an estimate into a laboratory measurement or personalized advice.