TSS Calculator Guide: Estimate Training Stress Score for Cycling and Running
Calculate Training Stress Score from duration, intensity, normalized power, FTP, or threshold-relative effort so you can plan weekly load instead of guessing.
A TSS calculator estimates Training Stress Score so you can compare workout load across rides, runs, and weeks. Searches like "TSS calculator", "training stress score calculator", "cycling TSS calculator", "running TSS calculator", and "IF calculator" usually come from athletes trying to answer one question: how hard was this workout really?
Duration alone is not enough. A two-hour easy ride and a two-hour threshold workout are not the same training load. The TrainingDojo TSS calculator combines duration and intensity so the session has planning context.
Open the free TSS calculator and use the result as the starting point for the training decisions below.
The Problem: Time Does Not Equal Training Load
Many athletes plan by hours, but adaptation and fatigue are driven by both volume and intensity. TSS gives a rough but useful way to compare workouts and understand weekly training stress.
For cyclists, TSS often comes from normalized power, FTP, and duration. For runners, it can be estimated from duration and threshold-relative intensity. Either way, the goal is not a perfect score; the goal is better planning.
What the TSS calculator Gives You
- Estimated Training Stress Score for the workout.
- Intensity Factor context when power or threshold-relative intensity is available.
- A training-load interpretation for easy, moderate, hard, and very hard sessions.
- A useful number for weekly planning, recovery decisions, and plan design.
How to Use the Calculator
- Enter duration accurately, including warmup and cooldown if they are part of the session.
- Use current FTP, normalized power, pace, or threshold-relative inputs depending on the workout type.
- Compare TSS to the rest of your week instead of judging it in isolation.
- Use high-TSS days carefully when stacking intensity.
Common Mistakes to Avoid
- Treating TSS as a trophy instead of a planning tool.
- Chasing high TSS on recovery days.
- Using an outdated FTP, which can distort every cycling TSS estimate.
- Forgetting that strength, heat, altitude, and life stress also affect fatigue.
Turn the Number Into Training
A TSS calculator helps answer whether a workout fits the week. If Tuesday already has hard intervals and Thursday has tempo, a giant Wednesday TSS score may be a problem. If the week is too light, you may need more aerobic volume.
TrainingDojo can help turn TSS targets into actual workouts, so the number becomes a plan instead of another dashboard metric.