How to Graph on a TI-84 Calculator (Complete Step-by-Step Guide)
Graphing on a TI-84 takes fewer steps than most people expect. Press Y=, type your equation, press GRAPH — and within seconds you have a plotted function on screen. This guide walks you through every part of that process, from setting up your first equation to adjusting the window, tracing values, finding intersections, and troubleshooting graphs that refuse to appear. Whether you're on a physical TI-84 Plus CE or using the free online TI-84 simulator, the steps are identical.
- Use Y= to enter equations and GRAPH to plot them instantly.
- The WINDOW button controls the visible range — always check it first if your graph isn't showing.
- ZOOM → ZStandard resets the window to a sensible default in one press.
- Use TRACE to read exact coordinates on any curve.
- To graph two functions, simply enter one in Y₁ and another in Y₂.
- No TI-84 at hand? The online graphing calculator works the same way in any browser.
What the Graphing Screen Actually Does
The TI-84's graphing screen is a coordinate plane — it shows an X axis and a Y axis with a visible rectangle of coordinates called the viewing window. Every function you type in Y= gets plotted as a curve inside that rectangle.
Three settings control what you see:
- Xmin / Xmax — how far left and right the window extends
- Ymin / Ymax — how far up and down the window extends
- Xscl / Yscl — the tick-mark interval on each axis
If a curve falls outside those bounds, you'll see a blank screen — which is the most common reason people think "my graph isn't working." Understanding this upfront saves a lot of frustration.
How to Enter a Function Using Y=
The Y= screen is where you define what to graph. The calculator stores up to 10 functions (Y₁ through Y₀) at once, though you can turn individual ones on or off.
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Press Y= (top-left of the keypad) The function editor screen opens. You'll see Y₁=, Y₂=, and so on.
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Move the cursor to Y₁ and type your equation Use the keypad to enter the expression. For X, press the X,T,θ,n key — not the letter X button. For example, to type 2X + 3, press 2 × X,T,θ,n + 3.
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Use the correct keys for exponents, fractions, and trig Square: press X,T,θ,n then x². Higher powers: use ^. Square root: 2nd → √. Sine: SIN.
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Press ENTER to confirm and move to Y₂ (optional) If you want a second function, enter it in Y₂ the same way.
Common Equation Examples
| Equation | What to Press on TI-84 |
|---|---|
| y = 2x + 1 | 2 X,T,θ,n + 1 |
| y = x² | X,T,θ,n x² |
| y = x³ − 4x | X,T,θ,n ^ 3 − 4 X,T,θ,n |
| y = sin(x) | SIN X,T,θ,n ) |
| y = √x | 2nd √ X,T,θ,n ) |
| y = 1/x | 1 ÷ X,T,θ,n |
Plotting the Graph — GRAPH Button
Once your equation is in Y=, press GRAPH (top-right of the keypad). The calculator draws the curve across the current window. Depending on the equation's complexity, this may take one to three seconds.
If the screen goes blank or you see only axes with no curve, the most likely cause is a window mismatch — the function's range of y-values falls outside Ymin/Ymax. Jump to the section on adjusting the window or just press ZOOM → 6:ZStandard to reset.
Adjusting the Window for Better Results
The default window after pressing ZStandard sets X from −10 to 10 and Y from −10 to 10. This works for basic linear and quadratic equations, but many functions — particularly those with large outputs or very small x-ranges — need a custom window.
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Press WINDOW A settings screen appears showing Xmin, Xmax, Xscl, Ymin, Ymax, Yscl, and Xres.
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Move to each field and type the new value, then press ENTER For example: Xmin = −5, Xmax = 5, Ymin = −20, Ymax = 20 for a cubic equation.
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Press GRAPH again to re-plot The curve now appears inside the adjusted window.
Window Settings Reference
| Setting | What It Controls | Typical Default |
|---|---|---|
| Xmin | Left edge of window | −10 |
| Xmax | Right edge of window | 10 |
| Xscl | Spacing between x-axis tick marks | 1 |
| Ymin | Bottom edge of window | −10 |
| Ymax | Top edge of window | 10 |
| Yscl | Spacing between y-axis tick marks | 1 |
| Xres | Pixel resolution (1 = highest detail) | 1 |
Using ZOOM to Rescale Quickly
The ZOOM menu gives you fast window presets so you don't have to type custom values every time. These are the options you'll use most often:
| ZOOM Option | What It Does | Best Used For |
|---|---|---|
| ZStandard (6) | Sets −10 to 10 on both axes | Resetting to a known starting point |
| ZDecimal (4) | Sets −4.7 to 4.7; each pixel = 0.1 | Clean decimal trace values |
| ZSquare (5) | Makes x and y scales equal | Circles, square graphs |
| ZTrig (7) | Window scaled for trig functions | sin(x), cos(x), tan(x) |
| ZoomFit (0) | Auto-adjusts Y to show the whole curve | When X range is correct but Y is off |
| Zoom In (2) / Out (3) | Zooms toward/away from cursor position | Exploring a specific region |
To use any ZOOM option: press ZOOM, then press the number of the option. The graph automatically redraws.
Reading Values with the TRACE Button
After graphing, press TRACE to activate a cursor that moves along the curve. As you press ← and → on the arrow keys, the x and y coordinates of the cursor's current position appear at the bottom of the screen.
- If you have multiple functions graphed, press ↑ and ↓ to switch between curves while in TRACE mode.
- Type a specific x-value and press ENTER while in TRACE mode — the cursor jumps to that exact x coordinate and shows the corresponding y.
- The function being traced is labeled in the top-left corner (Y₁, Y₂, etc.).
How to Graph Two Functions at Once
The TI-84 can plot multiple equations simultaneously, which is especially useful for comparing functions or setting up intersection problems.
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Press Y= and enter the first function in Y₁ Example: Y₁ = 2X + 1
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Press ENTER to move to Y₂, then enter the second function Example: Y₂ = X² − 3
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Press GRAPH Both curves appear on the same screen. On the TI-84 Plus CE, each equation gets a different color automatically.
To temporarily turn off one function without deleting it, go to Y=, move to that function's name (Y₁, Y₂, etc.), and press ENTER. The = sign will un-highlight, meaning the calculator will skip it when graphing. Press ENTER again to re-enable it.
Finding Where Two Graphs Intersect
This is one of the most-asked-about features in algebra and pre-calculus. The TI-84's intersect tool under the CALC menu finds the exact meeting point of any two curves.
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Graph both functions (follow the steps in the section above)
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Press 2nd → CALC (above the TRACE button) The CALCULATE menu appears.
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Select 5: intersect
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"First curve?" — press ENTER The cursor is on Y₁. Press ENTER to confirm it as the first curve.
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"Second curve?" — press ENTER The cursor moves to Y₂. Press ENTER to confirm.
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"Guess?" — move the cursor near the intersection, then press ENTER If there's only one intersection visible, just press ENTER. The calculator computes and displays the exact intersection point at the bottom of the screen.
Common Graphing Mistakes (and How to Fix Them)
Most graphing problems on the TI-84 come down to a handful of predictable issues. Here's a quick-reference list:
| Problem | Likely Cause | Fix |
|---|---|---|
| Blank screen after pressing GRAPH | Function is outside the current window | Press ZOOM → 6 (ZStandard), or ZOOM → 0 (ZoomFit) |
| ERR: WINDOW RANGE | Xmin ≥ Xmax or Ymin ≥ Ymax | Open WINDOW and correct the values |
| Only a horizontal line appears for y = sin(x) | Calculator is in Degree mode instead of Radian | Press MODE, highlight Radian, press ENTER |
| Equation entered but nothing graphs | The = sign in Y= is not highlighted (function is disabled) | Go to Y=, move cursor to the = sign, press ENTER to enable |
| Graph looks like a straight line but should curve | X-variable was typed as the letter X, not the X,T,θ,n key | Clear the equation and re-enter using X,T,θ,n |
| Graph cuts off at the edges | Window is too narrow for the curve's range | Use ZOOM → 0 (ZoomFit) to auto-scale Y, or expand Xmin/Xmax manually |
| ERR: SYNTAX during graphing | Typo in the equation (mismatched parentheses, missing operator) | Go back to Y=, review the expression, fix the typo |
No Calculator? Graph Right Here — Free
Practice every technique from this guide in your browser. No download, no signup — just open and graph.
Open Free TI-84 Online →Frequently Asked Questions
Why is my TI-84 graph screen blank after I press GRAPH?
The most common reason is that your equation's output values fall outside the current window range. Press ZOOM → 6 (ZStandard) to reset the window to −10 to 10 on both axes, then press GRAPH again. If the curve still doesn't appear, try ZOOM → 0 (ZoomFit), which automatically scales the Y-axis to fit the curve.
How do I type X when entering an equation on TI-84?
Always use the dedicated X,T,θ,n key (just below the ALPHA key on the left side of the keypad). If you use the ALPHA + X shortcut to type the letter X, the calculator treats it as a stored variable value, not a graphing variable — and your equation will plot as a flat horizontal line or not at all.
How do I change the window settings on TI-84?
Press the WINDOW button (second button from the left in the top row). You'll see six editable fields: Xmin, Xmax, Xscl, Ymin, Ymax, and Yscl. Use the arrow keys to navigate to each field, type your new value, and press ENTER. Then press GRAPH to redraw the plot with the new window.
Can I graph more than one equation at the same time?
Yes. Press Y= and enter your first equation in Y₁. Press ENTER to move down to Y₂ and enter a second equation there. When you press GRAPH, both curves appear on the same screen. The TI-84 Plus CE displays each function in a different color automatically. You can graph up to 10 functions simultaneously (Y₁ through Y₀).
How do I find the intersection of two graphs on TI-84?
After graphing both functions, press 2nd → CALC → 5: intersect. The calculator will ask you to identify the "First curve," "Second curve," and "Guess." Press ENTER for each prompt (or move the cursor near the intersection point before the final ENTER). The exact x and y coordinates of the intersection appear at the bottom of the screen.
Why does my sin(x) graph look flat on TI-84?
Your calculator is likely in Degree mode instead of Radian mode. In Degree mode, sin(1) through sin(10) all produce values extremely close to zero since those are tiny angles in degrees. Press MODE, use the arrow keys to highlight Radian on the third row, press ENTER, and then press GRAPH again. Also use ZOOM → 7 (ZTrig) for a window properly scaled for trig functions.
Can I graph on a TI-84 calculator online for free?
Yes. The TI-84 online simulator at ti84calculato.com works directly in any browser — no download, no account, no cost. Every step in this guide applies to the online version exactly as it does to the physical calculator. The site also includes a dedicated graphing calculator page if you want a streamlined graphing experience.
What is the TRACE button used for on TI-84?
TRACE places a movable cursor directly on a plotted curve. As you press the left and right arrow keys, the cursor slides along the line or curve and the x and y coordinates of the cursor's exact position appear at the bottom of the screen. This makes it easy to read specific output values without calculating them manually. If you type a number while in TRACE mode and press ENTER, the cursor jumps to that x-value instantly.
Putting It All Together
Graphing on a TI-84 follows a simple, repeatable workflow: enter your equation in Y=, set an appropriate window, press GRAPH, and then use TRACE or CALC to explore the results. The most important thing to remember is that a blank screen almost always means a window problem — not a broken calculator.
Once you're comfortable with single equations, practice graphing two functions together and using the intersect tool. Those two skills alone will get you through the majority of algebra, pre-calculus, and AP exam graphing problems.
For more hands-on practice and detailed walkthroughs of every TI-84 feature, visit the Guides & Tutorials section — or open the free online TI-84 calculator right now and follow along with the steps above.