Error codes
TI-84 Error Codes and How to Fix Them
A TI-84 error message is not a dead end — it is the calculator telling you exactly which part of the expression it could not read. Each guide below explains what the message means, the two or three causes behind it, and the keystrokes that clear it, including the complete error code reference.
Pick your error message
The calculator could not parse the expression you typed, so it refused to evaluate it.
TI-84 errorTI-84 error codesA reference table of the common TI-84 error messages, each with a plain-English meaning and the fix that clears it.
TI-84 errorERR: DOMAINThe value you gave a function or instruction lies outside the range it accepts, so no real answer can be returned.
TI-84 errorERR: INVALID DIMA plot, list or matrix has a dimension the calculator cannot use, so the operation is refused.
TI-84 errorERR: DIM MISMATCHAn operation combined lists or matrices whose dimensions do not agree, so the calculator cannot carry it out.
TI-84 errorERR: BOUNDA numeric search was given an interval whose bounds are in the wrong order, so no answer can be produced.
What the messages have in common
Almost every TI-84 error falls into one of four families. Knowing the family tells you where to look before you even read the full message:
- Syntax errors — the calculator cannot parse what you typed. Missing closing parenthesis, a stray comma, or a function that is not in the current mode.
- Dimension errors — the lists or matrices you are working with do not line up (different lengths, or a matrix size the operation cannot handle).
- Domain errors — the input is mathematically outside the function's domain, such as a negative number inside a square root in real mode.
- Graphing errors — the window, the table settings, or the equation itself makes the graph impossible to draw as configured.
If you are not sure which one you are looking at, start with the ERR: SYNTAX guide — it is the single most common message students search for.
TI-84 error questions
What does ERR: SYNTAX mean on a TI-84?
ERR: SYNTAX means the calculator could not read the expression you typed, so it refused to evaluate it. It is almost always a missing closing parenthesis, a comma where the calculator expected a different separator, a function used in the wrong mode, or an unfinished expression. Press 2 (Goto) to jump the cursor to the exact character the calculator objected to, which is usually the fastest way to spot the mistake.
What causes ERR: DOMAIN?
ERR: DOMAIN means the input you gave is outside the domain of the operation — for example taking the square root of a negative number while in real mode, taking the log of zero or a negative number, or asking for an inverse trigonometric ratio outside the range −1 to 1. It is a maths problem rather than a typing problem, so recheck the values and the mode before changing the expression.
How do I fix ERR: INVALID DIM?
ERR: INVALID DIM appears when a list or matrix operation receives dimensions it cannot use, such as plotting a scatter plot with two lists of different lengths, running a regression where L1 and L2 have unequal numbers of entries, or editing a matrix group of the wrong size. Check that L1 and L2 have exactly the same number of rows and clear any stray values below the last real entry.
Can a TI-84 error damage my calculator or delete my programs?
No. Error messages are the calculator refusing to continue, not a fault. Nothing is deleted and no data is corrupted. Pressing CLEAR or ON returns you to the home screen with your lists, programs and settings intact. The only operations that delete data are the deliberate options inside the memory menu, such as 2:Reset or 7:Clear Entries.