Day trading, minute by minute
A real session, minute by minute
InteractiveClick anywhere on the chart: the page gives you the New York time, the prices of that bar, the volume and where it stood against the opening range.
What day trading means
Day trading is a choice about duration, not a method. Whoever does it opens and closes positions inside the same session: when the exchange closes, they hold nothing. It is not a better forecast or a different instrument: it is the same chart looked at on a finer scale.
Fig. 1 · The position lives inside the day
- It opens while the market is trading and closes before the bell. The position is born and dies inside the same six and a half hours: there is no "tomorrow" in which to sort things out.
- No positions held overnight. Between one close and the next open a price can gap, and nothing can be done while the market is shut. A day trader never takes that jump.
- The price is the same as always. Only how closely you look at it changes: the same candles as a daily chart, but one a minute instead of one a session.
That is also why day traders close before the bell: between one close and the next open a price can gap, and nothing can be done about it while the market is shut. Whoever holds overnight takes that gap; a day trader, by definition, does not.
The shape of the day
A session is not flat: it moves and trades far more in some hours than in others. Below is the real volume of NVIDIA in the session of , half hour by half hour.
| Half hour (New York time) | Shares traded | Share of the day |
|---|---|---|
| 09:30 – 10:00 | 31.80M | 18.9% |
| 10:00 – 10:30 | 16.71M | 9.9% |
| 10:30 – 11:00 | 13.70M | 8.2% |
| 11:00 – 11:30 | 9.99M | 5.9% |
| 11:30 – 12:00 | 9.35M | 5.6% |
| 12:00 – 12:30 | 9.75M | 5.8% |
| 12:30 – 13:00 | 7.53M | 4.5% |
| 13:00 – 13:30 | 7.38M | 4.4% |
| 13:30 – 14:00 | 9.57M | 5.7% |
| 14:00 – 14:30 | 11.84M | 7.0% |
| 14:30 – 15:00 | 8.30M | 4.9% |
| 15:00 – 15:30 | 7.88M | 4.7% |
| 15:30 – 16:00 | 24.14M | 14.4% |
The first half hour traded 31.8 million shares and the last one 24.1, out of 167.9 million for the whole day: the two tails weigh more than the midday that sits between them. It is a shape that repeats: at the open the orders built up outside hours arrive, at the close positions are squared.
Fig. 2 · The two tails of the day
- At the open and at the close more shares change hands. The orders built up outside hours arrive and positions get squared: moves are wider and faster.
- In the middle hours volume drops. The same moves become slower and narrower, and a level that seemed to hold gets crossed without anything happening.
The opening range and its break
The opening range is the high and the low of the first 30 minutes of the session. There is nothing magic about it: it is simply the stretch of the day where most trading happened, and therefore the first reference everyone has in front of them. On the chart above it is the amber band.
Fig. 3 · The opening range and its break
- The first minutes draw a band. The high and the low of the first half hour: it is the stretch of the day where most trading happened, and therefore everyone's first reference.
- When price leaves the band, the range is said to be broken. Broken to the upside if it clears the high, to the downside if it loses the low.
- A break is a fact, not a promise. It says where price got to, not where it is going: the drawing beside this text is the same in both the cases below, and they end in opposite ways.
In the session of the opening range ran from $104.08 to $105.54. Price went above that high at 10:10, and kept climbing for the rest of the day.
Two days, two outcomes
Here is why a break is not a promise. These are two sessions of the same stock, NVIDIA, a few weeks apart: in both, price goes above the high of the first half hour. They end in opposite ways.
| The session | ||
|---|---|---|
| Opening range (high / low) | $105.54 / $104.08 | $143.20 / $140.74 |
| Goes above the high at | 10:10 | 11:28 |
| High of the day | $108.90 | $144.00 |
| Close | $108.78 | $139.95 |
| From the open to the close | 4.13% | -1.56% |
Fig. 4 · The break that comes back
- Price leaves the band and then trades back into it. The day ends on the other side, below the level it had just cleared.
- Anyone watching only the moment of the break sees exactly the same thing in both cases. The difference shows up afterwards, and afterwards is another story.
1The break that goes
- Price clears the opening range and never trades back inside it.
- Volume stays high as it moves away.
2The break that comes back
- Price clears the band by a little, then trades back into it.
- The day closes below the level it had cleared.
Two days are not a statistic, and this page does not turn them into one: they are two examples picked on purpose to show that the same fact — price leaving the band — leads to different outcomes. Anyone saying a break "works" is saying something the numbers do not say.
How much costs weigh
Trading inside the day means paying several times over what someone holding for months pays once: the spread between the buying and the selling price, and commissions. This is not bookkeeping detail: it is the part of the move that never arrives.
Fig. 5 · The same move, ten round trips or one
- A small move repeated ten times pays the costs ten times. Spread and commissions are paid on every round trip, going in and coming out.
- The same move taken once pays them once. That is not an opinion: it is a multiplication, and it is done beforehand with your own broker's numbers.
The arithmetic is done before, not after: what one round trip costs, how many round trips a day, and how far price has to move for the cost to be covered. It is arithmetic, and it is done with your own broker's numbers.
What time did it happen?
In the session of the high of the first half hour was $105.54. At what time did price first go above it?
Pick a time: the page tells you whether it is right and why.
What day trading is not
It is not a more profitable method. It is a shorter duration. Looking at price from close up does not make it more predictable: it makes decisions more frequent, and every decision has a cost.
It is not light work. It asks you to sit in front of the market in the hours when it moves, to decide quickly, and to be wrong often without the next day suffering for it. This page explains how a session is built; it does not tell anyone to trade one.
It is not what the numbers above measure. Two real sessions are here to show how an intraday chart is read, not to measure whether something works: that would take thousands of days and a calculation done properly, which is not what you are reading.
Deeper dives: the stop loss · support and resistance · trading volume · the trend · candlestick charts · pivot points.
Where to go from here
Technical strategiesThe other lessons in the guide
What is technical analysis
- the study of price and volume to recognise the trend and the levels
- three premises: price discounts everything, trends, history repeats
- exercise: uptrend, downtrend or sideways on three real charts
Candlestick chart
- the four prices of a session: body and shadows
- green and red, long and short bodies, long shadows, the doji
- find the candle on a real chart: the judge says yes or no with the numbers
Uptrend: higher highs and higher lows
- higher highs and higher lows: how to recognize an uptrend
- swing points, and the two signals that end a trend
- mark the higher lows yourself on a real chart
Support and resistance
- the level where the decline stopped, and the one where the rise stopped
- touches, time and volume: how much a level counts; once broken, it switches roles
- find the level yourself on a real chart: the judge counts the touches
Frequently asked questions
What is day trading?
It is buying and selling inside the same trading session: positions are opened and closed on the same day, and nothing is left open at the close. It differs from swing trading, where a position is held for days or weeks.
Why do day traders close before the bell?
Because between one session's close and the next one's open a price can gap, and nothing can be done while the market is shut. Closing before the bell means giving up that gap, for better and for worse.
What is the opening range of a session?
It is the high and the low of the first thirty minutes of trading. It is watched because a lot of volume goes through in that half hour and because it is the day's first reference, not because it contains a forecast.
Is day trading worth it?
This page does not answer that, and anyone who answers it quickly is usually selling something. What the numbers do say is that trading inside the day multiplies costs — spread and commissions are paid on every round trip — and that a break promises nothing: two sessions of the same stock can end in opposite ways.
Method and sources
| Source |
|---|
| John J. Murphy, Technical Analysis of the Financial Markets |
| Toby Crabel, Day Trading with Short Term Price Patterns and Opening Range Breakout |
The two NVIDIA sessions are those of and , minute by minute from our archive: 390 minutes each, from 9:30 to 16:00 New York time. They are fixed windows, chosen once and never changed. This guide explains how the tools work: it does not contain investment recommendations and promises no returns. Our method · license · report an error.
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