5K Time Predictor

By the Watta Team · Updated

Enter a recent result at another distance and get a 5K prediction using Paul's Law. A 7:12 2K (1:48.0 split) predicts a 5K of about 19:06.

5K Time Predictor

minsec
Predicted 5K Time18:361:51.6 /500m, from 1:45.0 /500m over 2000m

Paul's Law: about 5 seconds per 500m slower for every doubling of distance. A rule of thumb for trained rowers — your own aerobic/anaerobic balance can move the result by several seconds per 500m.

Rowing this later? Watta logs the real piece from a photo of your PM5 — free on iPhone.

The 5K a 2K result predicts

Computed with the same functions as the calculator above, so the two cannot disagree.

2K timePredicted 5K5K split
6:3017:211:44.1
7:0018:361:51.6
7:3019:511:59.1
8:0021:062:06.6
8:3022:212:14.1

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About This Calculator

The 5K time predictor estimates your 5,000-metre rowing ergometer performance from a result at another distance. The 5K erg test takes most trained rowers 17 to 22 minutes and relies predominantly on the aerobic system, which makes it a strong indicator of endurance fitness and threshold development. The prediction uses Paul's Law: the sustainable /500m split slows by about 5 seconds for every doubling of distance. From 2K to 5K that is 1.32 doublings, so a 2K split of 1:48.0 predicts a 5K split of about 1:54.6. Athletes with a strong aerobic base often beat the prediction; sprint-dominant athletes may fall short of it.

How This Works

Enter a recent maximal result from a known distance (500m, 1K, 2K, 6K or 10K). The calculator converts it to a /500m split, applies Paul's Law (5 seconds per 500m per doubling of distance) to estimate your sustainable 5K split, and converts that back to a finish time. The source distance matters: a 2K or 6K result predicts a 5K far better than a 500m sprint does.

Formula

Predicted split = known split + 5 × log₂(5000 / known distance); Predicted time = predicted split × 5000 / 500

Examples

Your 2K is 7:12 (1:48.0/500m)

Your predicted 5K is approximately 19:06 (1:54.6/500m).

You rowed a 6K at a 2:00.0 average split (24:00)

Your predicted 5K is approximately 19:47 (1:58.7/500m) — the shorter distance allows a slightly faster sustainable pace.

A beginner with a 2:20.0 2K split (9:20)

Predicted 5K split is approximately 2:26.6, for a finish of around 24:26. Beginners often see a smaller gap than the rule suggests because their 2K is rarely a true maximal effort.

Worked examples are generated from the same formulas as the calculator above.

Benchmarks

LevelValue
Recreational male20:00–24:00
Club male17:30–19:30
Collegiate male16:00–17:15
Recreational female22:00–26:00
Elite female17:00–18:30

More reference tables — 2K, 5K and 500m standards, watts by level, stroke rates and a split-to-watts table — are on the Stats & Benchmarks page.

In the Watta App

Watta logs every 5K you photograph and keeps a 5K personal best per machine, so predicted and actual times sit side by side as your fitness changes.

Frequently Asked Questions

How do I predict my 5K time from a 2K?
Add about 6.6 seconds per 500m to your 2K split (Paul's Law: 5 seconds per doubling, and 2K to 5K is 1.32 doublings). If your 2K split is 1:48.0 (a 7:12 2K), your estimated 5K split is about 1:54.6, giving a 5K of approximately 19:06. The simpler "add 5 seconds" shortcut gives 18:50.
What is a good 5K erg time?
As approximate guides for men: under 20:00 is a solid recreational time, under 18:00 competitive club, under 17:00 collegiate and under 16:00 elite. For women: under 22:00 recreational, under 20:00 competitive club, under 19:00 collegiate and under 17:30 elite. Age, weight class and rowing background all shift these bands.
How should I pace a 5K erg test?
Settle at your target split for the first 1,500m, hold steady or build slightly from 1,500–3,500m, push from 3,500–4,500m and sprint the final 500m. The 5K rewards patience early — going out too fast usually shows up as a fade after 3,000m.
Is the 5K or 2K a better fitness test for rowing?
They test different qualities. The 2K measures peak aerobic power and anaerobic capacity. The 5K measures sustained aerobic fitness and threshold. Many coaches use both: the 2K for selection and the 5K to assess aerobic base, especially in the off-season.

Related Content

2K Time PredictorRowing Pace CalculatorHR Zone Calculator10K Time Predictor2K TestA 2K test is a 2,000-metre maximal effort rowing ergometer test — the standard benchmark for indoor rowing performance, used for team selection and fitness assessment.Lactate ThresholdLactate threshold in rowing is the exercise intensity at which blood lactate begins to accumulate exponentially (approximately 4 mmol/L), representing the upper boundary of sustainable aerobic effort.Steady State RowingSteady state rowing is continuous, easy-paced erging at conversational intensity for 20–90 minutes — the UT2 band, 55–65% of 2K power at 18–22 spm — used to build aerobic fitness.Steady State Rowing Guide5K Rowing Workout Guide

Which Rowing App Should You Use?

Best Rowing Apps for Concept2Watta, ErgData, the Concept2 Logbook and Strava compared for logging, rankings and analytics.Best Rowing Apps 2026Every rowing app worth using, sorted by what you actually want from it.Concept2 Logbook AlternativesWhat the official logbook records, what it misses, and whether to run both.ErgData AlternativeLog your erg from a photo of the PM5 — no Bluetooth pairing needed.
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