# Which Flowchart Symbol Means Input Output? The Parallelogram

Canonical: https://sakura5.app/blog/which-flowchart-symbol-means-input-output/  
Published: 2026-11-01  
Author: the Sakura5 team · 8 min read  
Updated: 2026-11-01  
Publisher: Sakura5 (https://sakura5.app) · support@sakura5.app

> **TL;DR:** Which flowchart symbol means input output? The parallelogram. Learn what to label it, where it goes, and when to use Document or Manual Input instead.

![Which Flowchart Symbol Means Input Output? The Parallelogram](https://sakura5.app/img/blog/inline/which-flowchart-symbol-means-input-output-1.jpg)

The flowchart symbol that means input/output is the parallelogram — a rectangle with its left and right sides slanted in the same direction. You use it any time data enters the process (a user types a number, a file is read, a form arrives) or leaves it (a result is printed, a message is shown, a report is saved).

That one rule covers almost every flowchart you’ll draw for a class, a coding exercise or a work process. Where people get stuck is the edge of the rule: when an input is really just a step, when to use the more specific shapes like Document or Manual Input instead, and what to write inside the slanted box so it actually helps the reader.

This guide covers what the parallelogram looks like and where the convention comes from, the mistakes that make input/output boxes confusing, a step-by-step way to place them, a worked example of a grade calculator, the specialised shapes you’ll occasionally need, and short answers to the questions people ask most.

## Which flowchart symbol means input output: the parallelogram

The parallelogram is usually called the Data or Input/Output symbol in diagramming tools. In Microsoft Visio, Lucidchart and draw.io it sits in the basic flowchart panel next to the oval, the rectangle and the diamond. The ISO 5807 standard for flowchart symbols names it the data symbol and describes it as data with the medium unspecified — meaning you don’t care yet whether the data comes from a keyboard, a disk or a network, only that it crosses the boundary of the process.

That “crosses the boundary” idea is the useful part. A rectangle is work the process does. A parallelogram is the process talking to the outside world: taking something in or handing something out. If you keep that distinction in mind, you rarely need to look the symbol up again.

Three shapes get confused with it often enough to name:

- **Rectangle** — a process step, such as “Calculate total.” No data enters or leaves; something is done to data you already have.
- **Trapezoid** — the manual operation symbol, slanted on both sides toward the bottom. It looks like a parallelogram at a glance, but it means a step done by hand, not data moving.
- **Rectangle with a wavy bottom** — the document symbol. It is a specific kind of output (or input) that is a printed or written document.

If you want the other core shapes in one place, our guide to [flowchart symbols and meanings for beginners](https://sakura5.app/blog/flowchart-symbols-and-meanings-for-beginners/) walks through all six. The American Society for Quality also keeps a short reference on [flowchart symbols and when to use them](https://asq.org/quality-resources/flowchart).

## Why input/output boxes get drawn wrong

The shape itself is easy. The trouble is deciding what counts as input or output, and what to write inside.

![Why input/output boxes get drawn wrong — which flowchart symbol means input output](https://sakura5.app/img/blog/inline/which-flowchart-symbol-means-input-output-2.jpg)

*The trouble is deciding what counts as input or output, and what to write inside.*

The first mistake is using the parallelogram for every step that touches data. “Add tax to subtotal” uses data, but nothing enters or leaves the process, so it belongs in a rectangle. If every other box on your chart is slanted, the slant stops meaning anything.

The second mistake is the vague label. “Input” or “Output” on its own tells the reader nothing the shape doesn’t already say. The label should name the data: “Read exam score,” “Display final grade.”

The third mistake is forgetting outputs entirely. Beginners often draw the input at the top, a chain of calculations, and then go straight to the End oval. If the process produces something a person or another system will see, show it. A chart that computes a result and never outputs it describes a program that does nothing visible.

## How to place input and output symbols in a flowchart

These steps work for a programming exercise, a business process or a quick sketch on paper.

### 1. List what comes in and what goes out

Before you draw, write two short lists: every piece of data the process receives, and every piece it produces. For a login screen, that might be “username, password” in and “welcome screen or error message” out. Each item on those lists is a candidate parallelogram.

### 2. Put inputs right after Start, or right where they arrive

Most inputs sit directly below the Start oval, because the process can’t do anything until it has them. Some arrive mid-process — a confirmation code, a second form — and those go exactly where the process waits for them.

### 3. Start each label with a verb

Use “Read,” “Get,” or “Enter” for inputs and “Display,” “Print,” or “Save” for outputs. In programming flowcharts, the classroom convention is often “INPUT x” and “OUTPUT y”; if your teacher uses that, follow it.

### 4. Combine inputs that arrive together

If a form delivers name, email and phone at the same moment, one parallelogram labeled “Get name, email, phone” is clearer than three in a row. Split them only when they arrive at different times or one is validated before the next is requested.

### 5. Check every output has a reader

Trace each parallelogram near the bottom of the chart and ask who sees it. If nobody does, it may be a process step in disguise. If somebody does but the chart doesn’t show it, add the output before the End oval.

It helps to sort the inputs, steps and outputs before you choose any shapes. In [Mindmap AI](https://sakura5.app/mindmapai/) you can put the process name in the central node, branch out “Inputs,” “Steps” and “Outputs,” and then switch to the outline view to put everything in order. Once the list is right, drawing the chart takes a few minutes.

## A worked example: a grade calculator flowchart

Here’s a typical first-year programming exercise. Priya is writing a flowchart for a program that takes three test scores, averages them, and prints a letter grade. The rules: 90 or above is an A, 80 to 89 is a B, 70 to 79 is a C, anything below 70 is “Retake.”

![A worked example: a grade calculator flowchart — which flowchart symbol means input output](https://sakura5.app/img/blog/inline/which-flowchart-symbol-means-input-output-3.jpg)

*Here’s a typical first-year programming exercise.*

Her first draft had five parallelograms: one for each score, one for “Average,” and one for “Grade.” Two of those were wrong. Calculating the average is a process, so it moved into a rectangle. And because all three scores are entered at the same prompt, she combined them into one input box. The revised chart reads:

1. **Oval:** Start
2. **Parallelogram:** Read score1, score2, score3
3. **Rectangle:** average = (score1 + score2 + score3) / 3
4. **Diamond:** average ≥ 90? Yes leads to a parallelogram “Display A.”
5. **Diamond:** average ≥ 80? Yes leads to “Display B.”
6. **Diamond:** average ≥ 70? Yes leads to “Display C”; No leads to “Display Retake.”
7. **Oval:** End, with all four display boxes joining into it.

Test it with real numbers before handing it in. Scores of 92, 85 and 88 give 265 / 3 = 88.3, which fails the first diamond and passes the second, so the chart displays B. Scores of 60, 72 and 75 give 69, which fails all three diamonds and displays Retake. If any test path ends somewhere other than a display box and the End oval, the chart has a gap.

The final chart has one input, four outputs and one process box. That ratio is normal for a small program: data comes in once, and the branches decide which of several outputs the user sees.

## When to use a more specific input/output shape

The plain parallelogram is always acceptable. In detailed system or business charts, though, you’ll see specialised shapes that say *how* the data moves:

- **Manual input** — a rectangle with a sloped top edge, like a keyboard seen from the side. Use it when a person types or enters data by hand.
- **Document** — the wavy-bottom rectangle, for a printed report, invoice or form.
- **Multiple documents** — the same shape stacked, for a batch of documents.
- **Display** — a shape with a pointed left side and a curved right side, for output shown on a screen.
- **Stored data or database** — a cylinder for a database, used when data is written to or read from storage.

Use these only when the medium matters to the reader. A school exam will almost always expect the plain parallelogram. An operations chart for a warehouse might genuinely need to show that one input is a scanned paper form and another is a database lookup. If you mix the two styles on one chart, add a small legend.

If you’re drawing a full process rather than a single program, our guide on [how to make a flowchart for a process](https://sakura5.app/blog/how-to-make-a-flowchart-for-a-process/) covers scope, ordering and the unhappy paths. And for quickly drafting the branches of a bigger process, a Pro subscriber in [Mindmap AI](https://sakura5.app/mindmapai/) can type the topic and let AI suggest the steps, which is a fast way to spot a missing input before you commit to shapes.

## FAQ

**Which flowchart symbol means input output?**

The parallelogram means input or output in a flowchart. It is a rectangle with two sides slanted in the same direction, and it marks any point where data enters the process, such as a user typing a value, or leaves it, such as a result being displayed, printed or saved. Process steps use a plain rectangle instead.

**Is the input symbol different from the output symbol?**

No. In standard flowcharts, input and output share the same parallelogram, and the label tells the reader which one it is. Start the label with a verb like “Read” or “Enter” for input and “Display” or “Print” for output. Detailed charts may use specialised shapes like Manual Input or Document instead.

**What is the difference between a parallelogram and a trapezoid in a flowchart?**

A parallelogram has two parallel slanted sides leaning the same way and means data input or output. A trapezoid narrows toward the bottom, with both sides slanting inward, and means a manual operation — a step done by hand rather than by the system. They look alike at small sizes, so check the slant before choosing.

**Should a calculation go in a parallelogram?**

No. A calculation like “average = total / 3” is a process step and belongs in a rectangle, because no data enters or leaves the process at that point. Use the parallelogram only for the moment a value arrives from outside, such as user input or a file, or when a result is shown or saved.

About the app: [MindMap AI: Mind Map Maker](https://sakura5.app/mindmapai/) · App Store: https://sakura5.app/go/mindmapai?from=/blog/which-flowchart-symbol-means-input-output/