Split Comparison Tool

By the Watta Team · Updated

Enter two splits to see the gap in watts and what it means over a piece. 2:00.0 to 1:55.0 is 27 more watts (13%) — and 20 seconds over a 2K.

Split Comparison

:
203W
:
230W
Difference+28W (+13.6%)2:00.0 vs 1:55.0

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

What one second per 500m costs, at every pace

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

/500m splitWattsWatts for 1s fasterWatts for 5s faster
1:35408 W+13 W+72 W
1:40350 W+11 W+58 W
1:45302 W+9 W+48 W
1:50263 W+7 W+39 W
1:55230 W+6 W+33 W
2:00203 W+5 W+28 W
2:10159 W+4 W+20 W
2:20128 W+3 W+15 W

This is why a five-second personal best at 1:40 is a far larger performance change than the same five seconds at 2:20, and why comparing two rowers on seconds alone flatters the slower one.

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Which app should you use with your Concept2? →

Seven erg trackers ranked, free options first: ErgData, the Concept2 Logbook, Watta and more — what each is best for.

About This Calculator

The split comparison tool places two rowing splits side by side and calculates the difference in power and in finish time. Because of the cubic relationship between pace and power on a Concept2, the significance of a split difference depends heavily on the absolute pace. A 2-second gap between 2:10 and 2:08 is about 8 watts, while the same 2-second gap between 1:40 and 1:38 is about 22 watts. This tool quantifies those differences so you can judge what a pace target really costs and evaluate progress from session to session.

How This Works

Enter two /500m splits. The calculator converts both to watts using the Concept2 formula and shows the absolute and percentage difference in power. Multiply a split gap by the number of 500m segments in a piece to get the time difference: 5 seconds per 500m is 20 seconds over a 2K and 50 seconds over a 5K.

Examples

Comparing a 2:00.0 split to a 1:55.0 split

203W vs 230W — a 27W difference (13% more power). Over a 2K, this is a 20-second faster finish.

Comparing a 1:45.0 split to a 1:43.0 split

302W vs 320W — a 18W difference for 2 seconds per 500m. At faster paces, even a small improvement demands substantial extra power.

First half of a 2K at 1:48.0, second half at 1:46.0

A negative split: the second half needed about 16W more than the first (294W vs 278W) — good pacing discipline and a strong finish.

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

Benchmarks

LevelValue
1 second faster at 2:10≈ 4W extra
1 second faster at 2:00≈ 5W extra
1 second faster at 1:50≈ 7W extra
1 second faster at 1:40≈ 11W extra
1 second faster at 1:30≈ 16W extra

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 keeps every piece's split and watts, and shows each attempt against your previous one and your best at that distance, so session-to-session comparison happens without a spreadsheet.

Frequently Asked Questions

How much harder is 1:55 compared to 2:00?
A 1:55.0 split requires approximately 230 watts, compared with 203 watts at 2:00.0. That is 27 more watts, or about 13% more power. Over a 2K the 5-second gap is a 20-second faster finish (7:40 vs 8:00).
Why do small split differences matter so much?
The cubic power–speed relationship means each second of split costs progressively more power. At 2:00, one second faster costs about 5 extra watts. At 1:40, it costs about 11 extra watts. This is why gains get harder as you get faster.
How should I use split comparison for training?
Compare your splits across sessions of the same type. A 1–2 second improvement at the same heart rate is a real aerobic gain. Also compare race splits (first half against second half) to check pacing — ideally the second half is equal or faster.
Can I compare splits from different distances?
You can enter any two splits, but context matters. A 1:50 on a 2K test and a 2:00 on a 10K are not directly comparable — different distances use different energy systems and sustainable intensities. Use the distance predictors to translate between them first.

Related Content

Split to Watts ConverterRowing Pace Calculator2K Time PredictorWatts to Split ConverterSplit TimeSplit time is the pace expressed as the time it takes to row 500 metres on an ergometer, displayed in minutes and seconds (e.g. 2:00.0/500m).Negative SplitsNegative splits in rowing means completing the second half of a workout faster (lower split time) than the first half, indicating strong pacing and endurance.Watts (Rowing)Watts in rowing measure the power output on an ergometer, calculated from the pace using the Concept2 formula: Watts = 2.80 / pace³.How to Improve Your 2K Time

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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