Threshold Planner

Convert a 30-minute test into LT pace, HR, and race-ready tempo workouts.

Feed the calculator with field-test or race data to compute LT pace, speed, and heart rate, then deploy the outputs in tempo runs, cruise intervals, and marathon simulations with confidence.

Calculate LT Predict race pace

Quick answer

How do you estimate lactate threshold pace?

Use a controlled 30-minute field test.

Enter the distance and elapsed time from a hard but sustainable effort to estimate the pace you can hold around threshold.

Add heart rate when it is reliable.

A chest-strap average can help place LT relative to Zone 2 and race pace, but pace data alone is enough for a useful estimate.

Limit hard threshold work when recovery drops.

If sleep, appetite, mood, injury, or persistent fatigue changes, reduce intensity before using the next LT target.

🔥 Lactate threshold calculator

Enter a 30-minute test or race result to calculate LT pace, speed, heart rate, and recommended workouts.

Distance covered (km)

Use your 30-minute test distance or a recent race (e.g., 10K).

Elapsed time

Default is 30:00. Adjust if the test duration differed.

Average HR (optional)

Wear a chest strap for best results. Otherwise enter max HR to estimate.

Max HR (optional)

Used when average HR is unavailable to estimate LT around 90% of max.

LT pace

— min/km

— /mile

LT heart rate

— bpm

—

LT speed

— km/h

—

Recommended workouts

Tempo run (20–30 min): —
Cruise intervals (6–10 min reps): —

Limit LT work to once per week and keep easy days at least 15% slower than LT pace.

Frequently Asked Questions

These answers match the structured FAQ data on this page.

What is lactate threshold pace?

Lactate threshold pace is the fastest sustainable pace you can hold around one hour before fatigue rises sharply.

Can I estimate LT without heart-rate data?

Yes. Distance and time are enough to estimate LT pace. Heart-rate inputs improve guidance for threshold zones.

How often should I do LT workouts?

Most runners benefit from one dedicated LT session per week, balanced with easy aerobic mileage and recovery.

Last updated: February 25, 2026