# How to Improve Your 400m Time

> Why the 400 punishes pacing errors more than fitness, how to read your own split, and what a realistic in-season improvement looks like.

August 12, 2026 · 3 min read · Updated September 16, 2026

One caveat up front: your coach can see you race and can tell whether you died because you were unfit or because you ran the first 200 like it was a 200. That distinction changes everything, and only somebody watching can make it reliably.

The 400 rewards two things that are both trainable, and punishes one mistake that is free to fix.

## Fix the pacing first, because it costs nothing

Take your last race and split it in half. First 200, second 200.

- **Differential of about 1.0 to 1.5 seconds.** Well paced. Your improvement will come from fitness and speed.
- **Differential over 2.5 seconds.** You went out too hard. There is almost certainly a faster time available at your current fitness, purely from running it better.
- **Differential under 0.8 seconds.** You left something out there. You can afford to commit harder in the first 200.

Most high school 400 runners are in the second group, and most of them believe they need more fitness. They need a plan for the first 150 meters.

## The two qualities that matter

**Speed reserve.** How fast you are over 200 sets the ceiling for how comfortable 400 pace feels. If your 200 is 24.0, running 52 means holding close to your limit the whole way. Improve the 200 and the 400 gets easier without any extra endurance.

**Speed endurance.** The ability to keep producing force while lactate builds. This is the classically miserable part of 400 training, and it is trained by fast repeats over roughly 150 to 300 meters with incomplete recovery.

## What a realistic improvement looks like

People search for how to improve in two weeks. Honestly: in two weeks you can improve your **pacing**, your **start**, and your **freshness on the day**, and those together are often worth a second or more for a badly paced runner. What you cannot do in two weeks is meaningfully change your fitness.

Across a full season, a committed high school 400 runner improving by one to two seconds is normal. Larger jumps usually mean either a very young athlete or someone who was previously running the race badly.

## The last 100

Everyone slows down. The race is won by whoever slows down least, and that is partly trained and partly technical: as you tire, form collapses, stride shortens and you fight yourself. Practicing staying tall and relaxed while exhausted is a real session, not a motivational line.

## Make the progression visible

A season-long improvement curve is one of the more persuasive things a recruit can show, because it suggests the next season too. Keep your marks somewhere a coach can see them in order. To see what your current time is worth at 17 and 18 on the published age curve, use the [400m progression by age tool](https://trackreels.io/progression/400m).

Related: [what is a good 400m time](https://trackreels.io/blog/what-is-a-good-400m-time), [what a seed time is](https://trackreels.io/blog/what-is-a-seed-time), [how to email a college track coach](https://trackreels.io/blog/how-to-email-a-college-track-coach), and the 400m college ladder for [boys](https://trackreels.io/standards/400m/M) and [girls](https://trackreels.io/standards/400m/F).

Rankings, compare, standards and calculators are free here and stay free; a profile takes two minutes. [More TrackReels guides](https://trackreels.io/blog) · [Create your athlete profile](https://trackreels.io/signup)

## Keep reading

### [How to Get Faster in the 100m](https://trackreels.io/blog/how-to-get-faster-in-the-100m)

The parts of a sprint that actually respond to work, in the order they pay off, and the honest limits of anything you read online.

### [Good 200m Times by Age and Grade: Rate Your Time](https://trackreels.io/blog/good-200m-times-by-age-and-grade)

Published 2026 qualifying 200m times from California, Oregon and Missouri, the college recruiting ranges, the bend, the wind rule and the hand-time catch.

### [Is 11.5 a Good 100m Time? Rate Yours by Level](https://trackreels.io/blog/is-11-5-a-good-100m-time)

For a girl 11.5 is inside the D1 recruiting range. For a boy it is not a recruiting mark. Hand-timed, it is really an 11.74. The full ladder, D1 to NAIA.

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