Time Under Tension CalculatorFree online fitness & health calculator — instant results, no sign-up
Calculate set duration from repetition tempo and repetition count.
For general information only. This is not medical advice, diagnosis, dosing guidance or a treatment recommendation. Talk to a doctor or other qualified health professional about your health, pregnancy, or diet.
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About the Time Under Tension Calculator
The Time Under Tension Calculator estimates a set’s duration from the time spent lowering, pausing at the bottom, lifting, and pausing at the top of each repetition. It adds these four phases and multiplies the total by your repetition count. With the default tempo of 3 seconds lowering, 1 second at the bottom, 1 second lifting, and 0 seconds at the top, 10 repetitions take 50 seconds.
- Lowering phase (seconds)
- The time spent in the lowering, or eccentric, phase of each repetition, measured in seconds and defaulting to 3.
- Bottom pause (seconds)
- The time spent pausing at the bottom of each repetition, measured in seconds and defaulting to 1.
- Lifting phase (seconds)
- The time spent in the lifting, or concentric, phase of each repetition, measured in seconds and defaulting to 1.
- Top pause (seconds)
- The time spent pausing at the top of each repetition, measured in seconds and defaulting to 0.
- Repetitions
- The number of complete repetitions performed in the set, expressed as a whole-number count and defaulting to 10.
Formula and method
T = (t_lower + t_bottom + t_lift + t_top) × N = (3 + 1 + 1 + 0) × 10 = 50 seconds
- TEstimated set time under tension, in seconds.
- t_lowerLowering phase duration per repetition, in seconds.
- t_bottomBottom pause duration per repetition, in seconds.
- t_liftLifting phase duration per repetition, in seconds.
- t_topTop pause duration per repetition, in seconds.
- NNumber of complete repetitions in the set.
Add all four phase durations to find the planned duration of one repetition, then multiply by the repetition count. The default inputs give 3 + 1 + 1 + 0 = 5 seconds per repetition; multiplying by 10 gives a set time under tension of 50 seconds.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Lowering phase3 seconds
- Bottom pause1 seconds
- Lifting phase1 seconds
- Top pause0 seconds
- Repetitions10
Results
- Set time under tension50 seconds
How to use the Time Under Tension Calculator
- 1Enter the lowering phase duration in seconds; the default is 3.
- 2Enter the bottom pause duration in seconds; the default is 1.
- 3Enter the lifting phase and top pause durations in seconds; the defaults are 1 and 0, respectively.
- 4Enter the number of complete repetitions; the default is 10.
- 5Read the calculated set time under tension: the default inputs produce 50 seconds.
Reading your result
The “Set time under tension” output is the estimated total duration of the entered repetitions, including all four tempo phases. A result of 50 seconds means the set takes 50 seconds if you maintain the default tempo for all 10 repetitions. It does not include setup time or rest between sets.
Limitations
This calculation assumes every repetition uses the same tempo and includes each entered phase, including the top pause after the final repetition. It measures planned set duration rather than actual muscular tension: pauses, lockouts, or supported positions may reduce muscle loading even though their time is counted. It does not account for changes in tempo from fatigue, partial repetitions, extra rest between repetitions, load, or range of motion, and it cannot predict strength or muscle growth. Phase durations should be nonnegative, and repetitions should be a whole-number count.
Common questions
How does the default 3-1-1-0 tempo produce 50 seconds?+
The tempo represents 3 seconds lowering, 1 second pausing at the bottom, 1 second lifting, and 0 seconds pausing at the top. Each repetition takes 5 seconds, so 10 repetitions take 50 seconds.
Do bottom and top pauses count toward time under tension?+
Yes. The calculator adds both pauses to every repetition’s duration, whether or not the muscles remain actively loaded during those pauses.
What if my repetition tempo changes during the set?+
The calculator applies the same entered tempo to every repetition. If your tempo varies, the result is only an estimate; timing the actual set will give a better measure of its elapsed duration.
Does a longer calculated time under tension mean a more effective set?+
Not necessarily. This tool calculates duration only; training effects also depend on load, effort, range of motion, exercise choice, and overall programming.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.