What does ERR: SYNTAX mean on a TI-84 Plus™?

Syntax error. The calculator could not parse what you entered. Check for an unclosed bracket, two operators in a row such as `**`, or a stray character. Press [GRAPH] or [Y=] to return to the equation list, then use [DEL] to edit.

What does ERR: INVALID mean on a TI-84 Plus™?

Invalid argument. A valid command was given a value it cannot work with. Check the argument range. `asin(x)` needs −1 ≤ x ≤ 1, `ln(x)` needs x > 0, and a division cannot have a zero denominator.

What does ERR: DOMAIN mean on a TI-84 Plus™?

Domain error. The input falls outside the mathematical domain of the function. Restrict the input to where the function is defined. For `√x`, x must be non-negative. For `asin` and `acos`, the input must be between −1 and 1.

What does ERR: DIVIDE BY ZERO mean on a TI-84 Plus™?

Division by zero. The expression required division by zero at some point. Find where the denominator equals zero — that is usually a vertical asymptote rather than a true point on the graph. Adjust the window so the calculator does not sample exactly there, or use the table to inspect behaviour near the value.

What does ERR: OVERFLOW mean on a TI-84 Plus™?

Overflow. The result is too large for the calculator to represent. The value exceeded roughly 1×10⁹⁹. Check for an exponent that is too big, or a computation that grows without bound inside the current window.

What does ERR: NONREAL ANSWERS mean on a TI-84 Plus™?

Non-real answers. The calculation produced complex numbers while the calculator is in Real mode. Either change the window or function so the result is real, or switch to a+bi mode via [MODE] if you want the complex answer displayed.

What does ERR: STAT PLOT mean on a TI-84 Plus™?

Stat plot error. A statistical plot is turned on but its data is missing or invalid. Press [2nd] [Y=] to open the stat plot screen and either turn the plot off, or enter valid lists in [STAT] → Edit before graphing.

What does ERR: DIM MISMATCH mean on a TI-84 Plus™?

Dimension mismatch. Two lists or matrices have incompatible dimensions. For two-variable statistics the x and y lists must be the same length. For matrix multiplication, the column count of the first must match the row count of the second.

What does ERR: SINGULAR MAT mean on a TI-84 Plus™?

Singular matrix. The matrix has no inverse because its determinant is zero. A determinant of zero means the rows are linearly dependent — the system has no unique solution. Re-check the entries, or solve the system another way.

What does ERR: WINDOW RANGE mean on a TI-84 Plus™?

Window range error. The viewing window settings are inconsistent. Check Xscl, Yscl and the t-step. A scale of zero, or a maximum that is not greater than the minimum, triggers this. Reset with [ZOOM] 6:ZStandard.

What does ERR: LINK mean on a TI-84 Plus™?

Link error. A connection to another calculator or to a computer failed. Check the cable or the connection on both ends and confirm both devices are on. This does not affect any calculation on the device itself.

What does ERR: NO SIGN CHG mean on a TI-84 Plus™?

No sign change. The solver looked for a root between two points but the function did not cross zero there. Pick an interval where the function actually changes sign — one end positive, the other negative. If it touches zero without crossing, the solver cannot find it this way.

What does ERR: BREAK mean on a TI-84 Plus™?

Break. A running program or loop was interrupted. Press [ON] to stop execution. Re-run the program if the interruption was accidental.

What does ERR: ARCHIVED mean on a TI-84 Plus™?

Archived variable. The program tried to write to a variable that is archived. Unarchive the variable first via [2nd] [+] (MEM) → 2:Mem Mgmt/Del, find the variable, and change its archive status.

Reference

TI-84 Plus™ Error Codes

Every error the handheld can throw, what actually causes it, and the fix — written for someone standing at the keyboard with a deadline.

The four-step routine

Almost every error clears the same way, and the routine matters more than the specific message. The key detail: the calculator highlights the offending expression, so go where it points rather than guessing.

Read which error it is
Note the name and the highlighted position before changing anything. Most people start editing immediately and lose the clue.
Go to where it points
Press [GRAPH], [Y=] or [STAT] as prompted. This drops you at the exact expression that triggered the error.
Fix the cause, not the message
Close the bracket, correct the syntax, or move the domain so the calculation is defined. Clearing the dialog without changing anything just brings it back.
Re-run and check
Press [GRAPH] or [ENTER]. If the error returns, the real cause is somewhere you have not looked yet.

Every error, explained

14 errors, ordered by how often you are likely to hit them. Each one lists the cause, the fix, and the situation where it most commonly comes up.

ERR: SYNTAX

Syntax error

Cause: The calculator could not parse what you entered.
Fix: Check for an unclosed bracket, two operators in a row such as `**`, or a stray character. Press [GRAPH] or [Y=] to return to the equation list, then use [DEL] to edit.
You hit this when: Entering `y=x^-2` where the negative sign was used instead of the subtraction key, or leaving a bracket open at the end of a long expression.

ERR: INVALID

Invalid argument

Cause: A valid command was given a value it cannot work with.
Fix: Check the argument range. `asin(x)` needs −1 ≤ x ≤ 1, `ln(x)` needs x > 0, and a division cannot have a zero denominator.
You hit this when: Taking the logarithm of zero or a negative number, or an inverse trig function outside its domain.

ERR: DOMAIN

Domain error

Cause: The input falls outside the mathematical domain of the function.
Fix: Restrict the input to where the function is defined. For `√x`, x must be non-negative. For `asin` and `acos`, the input must be between −1 and 1.
You hit this when: Graphing `√x` over a window that includes negative x values.

ERR: DIVIDE BY ZERO

Division by zero

Cause: The expression required division by zero at some point.
Fix: Find where the denominator equals zero — that is usually a vertical asymptote rather than a true point on the graph. Adjust the window so the calculator does not sample exactly there, or use the table to inspect behaviour near the value.
You hit this when: Graphing `1/x` through x = 0, or a rational function evaluated at a root of its denominator.

ERR: OVERFLOW

Overflow

Cause: The result is too large for the calculator to represent.
Fix: The value exceeded roughly 1×10⁹⁹. Check for an exponent that is too big, or a computation that grows without bound inside the current window.
You hit this when: Plotting a high-power polynomial over a wide window, so intermediate terms exceed the limit before they cancel.

ERR: NONREAL ANSWERS

Non-real answers

Cause: The calculation produced complex numbers while the calculator is in Real mode.
Fix: Either change the window or function so the result is real, or switch to a+bi mode via [MODE] if you want the complex answer displayed.
You hit this when: Solving `x^2 + 4 = 0` in Real mode, or graphing a function whose values are imaginary over part of the window.

ERR: STAT PLOT

Stat plot error

Cause: A statistical plot is turned on but its data is missing or invalid.
Fix: Press [2nd] [Y=] to open the stat plot screen and either turn the plot off, or enter valid lists in [STAT] → Edit before graphing.
You hit this when: Leaving Plot1 switched on after clearing a list, then pressing [GRAPH].

ERR: DIM MISMATCH

Dimension mismatch

Cause: Two lists or matrices have incompatible dimensions.
Fix: For two-variable statistics the x and y lists must be the same length. For matrix multiplication, the column count of the first must match the row count of the second.
You hit this when: Performing regression with an x list of 10 entries and a y list of 9.

ERR: SINGULAR MAT

Singular matrix

Cause: The matrix has no inverse because its determinant is zero.
Fix: A determinant of zero means the rows are linearly dependent — the system has no unique solution. Re-check the entries, or solve the system another way.
You hit this when: Attempting `A⁻¹` on a matrix whose rows are multiples of each other.

ERR: WINDOW RANGE

Window range error

Cause: The viewing window settings are inconsistent.
Fix: Check Xscl, Yscl and the t-step. A scale of zero, or a maximum that is not greater than the minimum, triggers this. Reset with [ZOOM] 6:ZStandard.
You hit this when: Typing a scale of 0 by accident when editing the window, or leaving Xmax equal to Xmin.

ERR: LINK

Link error

Cause: A connection to another calculator or to a computer failed.
Fix: Check the cable or the connection on both ends and confirm both devices are on. This does not affect any calculation on the device itself.
You hit this when: An interrupted transfer between two calculators.

ERR: NO SIGN CHG

No sign change

Cause: The solver looked for a root between two points but the function did not cross zero there.
Fix: Pick an interval where the function actually changes sign — one end positive, the other negative. If it touches zero without crossing, the solver cannot find it this way.
You hit this when: Running [CALC] 2:zero on an interval that lies entirely above or below the x-axis.

ERR: BREAK

Break

Cause: A running program or loop was interrupted.
Fix: Press [ON] to stop execution. Re-run the program if the interruption was accidental.
You hit this when: Pressing [ON] during a long program to halt it.

ERR: ARCHIVED

Archived variable

Cause: The program tried to write to a variable that is archived.
Fix: Unarchive the variable first via [2nd] [+] (MEM) → 2:Mem Mgmt/Del, find the variable, and change its archive status.
You hit this when: Running a program that stores to a list you archived to free memory.

Why the same errors keep coming back

Three causes account for the large majority of TI-84 Plus™ errors, and all three are preventable before you ever press [GRAPH].

Unclosed brackets

A missing ) at the end of a long expression is the single most common trigger for ERR: SYNTAX. Count your brackets before you graph — the calculator will not count them for you, and it will not tell you which one is missing.

A window that does not include the curve

An empty or nonsensical graph is usually the window rather than the equation. Press [ZOOM] then 6:ZStandard before you conclude anything is broken. Most "my calculator is wrong" moments resolve here.

Real mode producing complex answers

Graphing a function that is imaginary over part of the window produces ERR: NONREAL ANSWERS. Either narrow the window so the function stays real, or switch to a+bi mode via [MODE] if you want the complex values displayed.

Checking your work without the handheld

The online TI-84 Plus™ on this site reproduces the keypad layout, so you can rehearse the fix before you are at the physical device. For the underlying maths, the graphing calculator shows the working behind each result rather than only the number.