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Swim Training Zones Calculator

Calculate five swim training zones from your Critical Swim Speed (CSS) pace. Structure workouts by intensity for optimal improvement.

Inputs

sec

Results

Zone 3 Threshold (slow)

100 sec/100m

Zone 3 Threshold (fast)

106 sec/100m

Zone 1 Recovery (slow)118 sec/100m
Zone 1 Recovery (fast)124 sec/100m
Zone 2 Endurance (slow)108 sec/100m
Zone 2 Endurance (fast)113 sec/100m
Zone 4 VO2max (slow)93 sec/100m
Zone 4 VO2max (fast)98 sec/100m
Zone 5 Sprint (slow)77 sec/100m
Zone 5 Sprint (fast)88 sec/100m
How to Use This Calculator
  1. Enter your CSS Pace (Critical Swim Speed) per 100m in seconds.
  2. Review all five training zones from Zone 1 Recovery through Zone 5 Sprint.
  3. Each zone shows a pace range in seconds per 100m.
  4. Use Zone 2 (Endurance) for base aerobic work and Zone 3 (Threshold) for CSS interval sets.
  5. Use Zone 4 and Zone 5 for short, high-intensity sprint sets.

How the result changes with CSS Pace per 100m

CSS Pace per 100mZone 3 Threshold (slow)Zone 3 Threshold (fast)
6563 sec/100m67 sec/100m
103100 sec/100m106 sec/100m
148144 sec/100m152 sec/100m
185179 sec/100m191 sec/100m

What each input means

CSS Pace per 100m
Your Critical Swim Speed pace in seconds per 100m. Use the CSS Calculator to determine this from time trials.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    CSS Pace per 100m = 103 = 1 input(s) provided
  2. Calculate Zone 3 Threshold
    Zone 3 Threshold
    100 = 100
  3. Calculate Zone 3 Threshold
    Zone 3 Threshold
    106 = 106
  4. Calculate Zone 1 Recovery
    Zone 1 Recovery
    118 = 118
  5. Calculate Zone 1 Recovery
    Zone 1 Recovery
    124 = 124

Engine last updated . Checked against 1 independently-derived test — how we verify calculators.

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