Short answer: Algorithmic trading, or algo trading, is a method in which a computer program places buy and sell orders automatically once conditions the trader set in advance are met. Manual trading is the opposite: a person watches the market and places each order by hand. The core difference is who makes the decision at the moment of each trade.
Last reviewed: 12 November 2026
At a glance
| Feature | Algorithmic trading | Manual trading |
|---|---|---|
| Who places each order | A computer program, following rules set in advance | A person, decision by decision |
| Speed of execution | Orders can be executed within milliseconds | Limited by how fast a person can react |
| Effect of emotion | Follows its rules strictly, not swayed by fear, greed or panic | Decisions can be pushed by fear, greed or panic |
| Number of stocks watched | A single algorithm can watch many stocks at once | A manual trader can realistically track a limited number |
| Testing before real money | Can be tested on historical data | Generally cannot be tested in the same way |
What does algorithmic trading actually mean?
An algorithm is a set of step-by-step instructions that a computer carries out. In trading, the instructions are conditions such as “buy this stock if its price falls to a certain level” or “sell if it rises by a set amount.” The trader writes these conditions before the market opens or before a strategy runs, and the program then waits for them to be met.
The program does not decide what is worth owning. It only carries out the rules it was given. If the rules are poorly chosen, the program will follow them just as faithfully as well-chosen ones.
How fast can each approach act?
Algorithmic systems can execute orders within milliseconds, which is a thousandth of a second. A human trader, however carefully focused, cannot react that quickly. A person must see the price change, think, and then click or call in an order.
Speed works in both directions. If a rule contains a mistake, an algorithm can place many orders before anyone notices. A manual trader who makes an error usually makes it one order at a time, which gives more chances to pause and correct course.
Why do emotions matter less for an algorithm?
Manual trading decisions can be pushed by fear, greed or panic. A trader may hold a falling stock too long because they hope it will recover, or sell in a rush because the price has dropped sharply. These reactions are human, and they are hard to switch off in the middle of a fast-moving market.
An algorithm follows its programmed rules strictly and is not swayed by these feelings. The catch is that it also cannot adjust for situations its rules did not anticipate. A rule written for ordinary conditions will still apply the same way in unusual ones, unless the trader has programmed an exception.
How many stocks can each approach watch?
A single algorithm can watch many stocks at the same time. A manual trader can realistically track only a limited number of opportunities, because each one needs attention.
Hypothetical example, with figures invented for illustration only: Suppose a trader’s rule is to buy 200 shares of a company when its price reaches ₹250 per share. The cost of that one purchase is 200 × ₹250 = ₹50,000. A program can apply the same rule to ten different stocks simultaneously, while a person watching the screen may only keep an eye on two or three. The program’s reach is wider, but each rule still needs to be sound before it is used across many stocks.
Can an algorithm be tested before real money is used?
Yes. Algorithmic strategies can be tested on historical data, meaning past price records, to see how the rules would have performed. Manual trading generally cannot be tested in the same way, because a person cannot replay past markets and make the same decisions with the same hindsight-free information.
Testing has its limits. A strategy that worked on past data may not work on future data, and a test only covers the situations that appear in the records used. A passing test is evidence about the past, not a guarantee about what happens next.
Is algo trading the right approach for everyone?
This article does not assume your income, goals or appetite for risk, and it does not suggest whether you should use either method. Algo trading requires the trader to define rules precisely, which is a different skill from reading the market and deciding on the spot. Manual trading requires judgement under pressure, which many people find difficult to sustain.
Both methods carry risk of loss. The differences described here change how that risk shows up, not whether it exists.
Frequently asked questions
Does algo trading mean the computer decides what to buy?
No. The trader sets the rules in advance, and the program places orders only when those rules are met. The program carries out the trader’s instructions rather than choosing its own.
Are algorithms faster than human traders?
Yes, algorithmic systems can execute orders within milliseconds, far faster than a human trader can react. That speed can also spread a mistake in a rule quickly.
Can you test an algorithm before using real money?
Yes. Algorithmic strategies can be tested on historical data before real money is used. Manual trading generally cannot be tested in the same way.
Sources and last check
Facts in this article were checked against the sources below on 12 November 2026. Rules and figures can change; check the primary source before acting.
- upstox.com (broker education)
- groww.in (broker education)
- kotakneo.com (broker education)
This article is general information, not investment advice. MyFinanceBandhu is not a SEBI-registered investment adviser.