TSS Calculator
Enter your ride duration, Normalized Power and FTP to calculate your Training Stress Score (TSS) — a single number that captures how much training load a ride puts on your body.
Learn About TrainerRoadTraining Stress Score
64
Intensity Factor 0.80
Same training load as 38 min at your FTP
Typical Workout
Where most weekday structured workouts land.
TSS says nothing about how a ride felt — a steady hour and a brutal set of intervals can score the same. What counts as a lot is relative to your own training.
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What Is Training Stress Score (TSS)?
Training Stress Score (TSS) is a single number that sums up how hard a ride was, combining how long you rode with how intense it was relative to your FTP. One hour at your FTP equals 100 TSS by definition, so a ride at 150 TSS was roughly one-and-a-half times that stress.
Combines Time and Intensity
A short, hard ride and a long, easy one can carry the same training load — TSS puts both on one scale.
Benchmarked to Your FTP
Intensity is measured against your FTP, so the same ride scores differently as you get fitter.
The Currency of Training Load
Adding up TSS across days and weeks shows how much stress you are carrying — and when it is time to recover.
How TSS Is Calculated
TSS multiplies the length of your ride (in hours) by the square of your Intensity Factor — your Normalized Power divided by your FTP — and then by 100. The square is what makes harder efforts count for so much more: riding at 90% of FTP is far more stressful than riding at 60%.
TSS Hours IF² 100
Hours Ride duration, in hours
IF² Intensity Factor — Normalized Power divided by FTP — squared
100 One hour at FTP equals 100 TSS
Typical TSS for Common Rides
These examples come straight from the formula — enter your own numbers in the calculator above to see where your ride lands.
Recovery Spin
Easy spinning that adds barely any training load.
30 min IF 0.50
13 TSS
Endurance Ride
Steady aerobic riding that builds your base.
1 hour IF 0.65
42 TSS
Sweet Spot Workout
Structured intervals just below your FTP.
1 hour IF 0.85
72 TSS
Threshold Workout
One hour at FTP — 100 TSS by definition.
1 hour IF 1.00
100 TSS
Long Endurance Ride
Duration drives up load even at an easy pace.
3 hours IF 0.65
127 TSS
Century Ride
A big day out — high load that demands recovery.
5 hours IF 0.70
245 TSS
How Much TSS Should You Do in a Week?
Weekly TSS is simply the sum of your rides, so it follows from two things: the hours you can train and how hard those hours are. Every number below comes from the same formula this calculator uses — find the rides that look like your week and add them up.
| Intensity | 30 min | 45 min | 1 hour | 90 min | 2 hours | 3 hours | 4 hours | 5 hours | 6 hours |
|---|---|---|---|---|---|---|---|---|---|
| Recovery IF 0.55 | 15 | 23 | 30 | 45 | 61 | 91 | 121 | 151 | 182 |
| Endurance IF 0.65 | 21 | 32 | 42 | 63 | 85 | 127 | 169 | 211 | 254 |
| Tempo IF 0.75 | 28 | 42 | 56 | 84 | 113 | 169 | 225 | 281 | 338 |
| Sweet Spot IF 0.85 | 36 | 54 | 72 | 108 | 144 | 217 | 289 | 361 | 434 |
| Threshold IF 0.95 | 45 | 68 | 90 | 135 | 181 | 271 | 361 | 451 | 541 |
| At Your FTP IF 1.00 | 50 | 75 | 100 | 150 | 200 | 300 | 400 | 500 | 600 |
| Above Your FTP IF 1.05 | 55 | 83 | 110 | 165 | 221 | 331 | 441 | 551 | 662 |
- Sustainable in training
- Race-level — at the edge of what you can hold
- Beyond what anyone holds for that long
Notice how the red corner grows with time: nobody rides four hours at their FTP. So if one of your own rides lands in a red cell, the FTP you entered is almost certainly too low — and every TSS you have logged against it is overstated.
That is the problem AI FTP Detection solves: TrainerRoad updates your FTP from the rides you already did, with no fitness test, so your training load is measured against a number that is actually yours.
The direction matters more than the total: raise weekly TSS gradually, and back off before fatigue outruns fitness. Balancing that week to week is exactly what TrainerRoad’s adaptive training does for you — every plan adjusts to the load you can actually absorb.
TSS Questions, Answered
What does TSS stand for?
TSS stands for Training Stress Score. It combines how long you rode with how hard you rode relative to your FTP, so one number describes the whole ride. One hour at your FTP is 100 TSS by definition, which is the anchor every other score is measured against.
What is a good TSS for one ride?
There is no objective good score — it depends on your experience, your fitness and the job that ride has in your week. The one fixed reference point is the definition: 100 TSS is an hour at your FTP. A beginner might build a whole week around 260 TSS; an experienced rider can cover that in a weekend.
How much TSS should I do in a week?
Weekly TSS follows from the hours you can train and how hard those hours are — six endurance hours at an Intensity Factor of 0.65 is about 254 TSS, while six hours of Sweet Spot work at 0.85 is about 434. Raising that number gradually matters far more than hitting any particular total.
Can I calculate TSS without a power meter?
The standard formula needs Normalized Power, so it needs power data — from a power meter or a smart trainer. Heart-rate-based estimates exist, but heart rate lags hard efforts and drifts with heat and fatigue, so they are least reliable exactly where TSS matters most: short, intense rides.
Is TSS the same as Intensity Factor?
No. Intensity Factor is how hard a ride was relative to your FTP — Normalized Power divided by FTP — with no sense of time. TSS multiplies that intensity, squared, by the hours you rode. That is why a hard 30-minute effort and an easy three-hour ride can score the same.
Why did my TSS drop after my FTP went up?
TSS is measured against your current FTP, so the same watts count for less once you are fitter. That is exactly why an accurate FTP matters: TrainerRoad’s AI FTP Detection updates yours from your ride data — no fitness test required — so every TSS you log stays honest.
Let TrainerRoad Track It for You
Adding up TSS by hand only tells you what you already did. TrainerRoad turns it into a plan: AI FTP Detection keeps your FTP accurate without a fitness test, and your training load is balanced automatically so every week builds fitness without burying you in fatigue.
Ready to stop doing the math? Start a structured training plan that manages your training load for you.
TrainerRoad is cycling’s most effective training system: structured workouts, science-based plans, and AI that personalizes everything to you — including your FTP.
How AI FTP Detection Works
Connect Your Rides
Import your ride history from Garmin, Strava, Wahoo, and more.
AI Analyzes Every Ride
TrainerRoad AI studies your power data and how your fitness responds to training.
Your FTP, Detected
Accept your new FTP with one tap — every workout adjusts to it instantly.
30 Day Money Back Guarantee
“AI FTP Detection is seriously amazing and so accurate!”
Real Riders. Real Results.
“It helped me increase my FTP by 40w in 4 months. What else do I need to say?”
“TR has taken me from a Cat 5 to a Cat 1 (pending approval) in about 6 seasons… a 6th place finish at nationals.”
“Just started cycling less than 12 months ago… Started at 195 FTP and with TrainerRoad progression I'm sitting at 272.”
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AI FTP Detection FAQ
Common questions about how TrainerRoad detects your FTP from your riding — answered by the team.
What TSS Is Good For — and Where It Misleads
The longer read on Training Stress Score: what it captures, and the rides where the number flatters you.
Automatic Ride Sync
Connect Garmin, Wahoo or Strava and every ride is scored for you — no manual entry.
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