Most scientific calculators reset through a simple key combination, usually involving a shift or second-function key followed by a reset option in a menu. The exact steps depend on your brand and model, but the process rarely takes more than a few seconds. Below you’ll find the specific sequences for every major brand, plus what to do if your calculator is frozen and won’t respond to button presses at all.
Casio Calculators
Casio offers the most common scientific calculators in classrooms worldwide, including the fx-82, fx-85, fx-350, fx-570, and fx-991 series. The reset process is nearly identical across all of them.
Press SHIFT, then 9 (which activates the RESET menu). You’ll see options for different levels of reset. Select “Initialize All” and then confirm by selecting “Yes.” The calculator will return every setting to its factory default and wipe all stored data from memory. On ClassWiz models like the fx-991EX, the menu labels are the same: SHIFT, 9, then choose your reset level and confirm.
Choosing the Right Reset Level
Casio gives you a choice between a partial and full reset, and picking the right one can save you from clearing data you still need:
- Setup Data: Resets your calculation mode, angle unit, and display settings back to defaults, but leaves your stored variables and memories intact. This is the right choice if your calculator is giving unexpected results because a setting got changed.
- Initialize All: Resets all settings (except screen contrast and auto power off) and erases everything in memory. Use this when you want a true clean slate or when a partial reset didn’t fix the problem.
Texas Instruments Calculators
The TI-30X IIS is one of the most widely used scientific calculators in the U.S. It has two reset methods, one faster than the other.
The quick method: press ON and CLEAR at the same time. This resets the calculator immediately with no confirmation screen, so be sure you’re ready to lose any stored data.
The menu method gives you a confirmation step. Press 2nd, then RESET. You’ll see a small menu that reads “RESET: N Y.” Use the right arrow key to move the cursor to Y, then press ENTER. The screen will briefly display “MEM CLEARED” to confirm the reset is complete. This method is safer since it gives you a chance to back out.
HP Calculators
The HP 35s and similar HP scientific models use a CLEAR menu with several options, giving you fine-grained control over what gets erased. Press the left shift key (often labeled with a small arrow), then CLEAR. You’ll see a numbered menu:
- 1 (X): Clears only the current display register.
- 2 (VARS): Clears the 26 variable storage registers (A through Z).
- 3 (ALL): Clears the stack, all variables, and all stored programs. This is the full reset.
If you select option 3, the calculator will ask “CLR ALL? Y N” as a safety check. Use the left arrow key to highlight Y, then press ENTER. Options 4, 5, and 6 handle more specialized clearing for statistical registers, the calculation stack, and indirect registers, but most users only need option 3 for a complete reset.
Canon Calculators
Canon scientific calculators like the F-715SG use a slightly different approach. To return the calculation mode to its defaults without erasing your stored variables, press MODE followed by AC. This resets your mode to standard computation, your angle unit to degrees, and your display format to normal.
For a full initialization that also clears variable memories and the replay history, press SHIFT (labeled “All” in this context) followed by AC. This is the option to use when you’re not sure what settings have been changed and want everything back to factory condition.
Using the Physical Reset Button
If your calculator screen is frozen or completely unresponsive to key presses, a software reset won’t help. Most scientific calculators have a small pinhole on the back of the case, typically labeled “P” or “RESET.” Turn the calculator face down, find the hole, and press it once with a straightened paperclip or the tip of a mechanical pencil. Don’t use anything sharp enough to damage the internal contact. One gentle press is enough. The screen will go blank, and the calculator will load its default settings the next time you power it on.
Only use the pinhole reset when the calculator is genuinely unresponsive. It performs a hardware-level reset that clears everything, and on some models it’s equivalent to removing and reinserting the battery.
Common Problems a Reset Fixes
A reset is the right move when your calculator is stuck in the wrong mode or producing results you don’t expect. The most frequent issues include:
Your angle unit is set to radians instead of degrees (or vice versa). This is the single most common reason students get wrong answers in trigonometry. A reset snaps the calculator back to degrees, which is the default on nearly every model. If your sine, cosine, or tangent calculations look wildly off, this is almost certainly the cause, and a simple settings reset will fix it without erasing your stored data.
A “Syntax Error” appears when you try to run a calculation. This means the expression you entered has a structural problem, like mismatched parentheses or an operator in the wrong position. Pressing AC or CLEAR usually clears the error so you can re-enter the expression. A full reset isn’t necessary for a one-time syntax error, but if errors keep appearing on calculations that should work, resetting the calculator rules out a corrupted setting.
“Math Error” shows up when you ask the calculator to do something mathematically impossible, such as dividing by zero or taking the square root of a negative number while in real-number mode. A “Stack Error” means your expression is too complex for the calculator to process in one step. Neither of these requires a reset. They’re resolved by simplifying or correcting your input. But if you’re seeing errors on basic calculations that definitely should work, a full initialization is a reasonable troubleshooting step.
What a Reset Does Not Fix
A software or menu-based reset won’t help if the screen is physically damaged, if the solar panel has degraded to the point where it can’t power the display, or if the battery is dead. If your calculator powers on but the screen is faded or shows partial characters, try replacing the battery before resetting. Most scientific calculators use a single CR2032 or LR44 coin cell that costs about a dollar and takes under a minute to swap. After replacing the battery, Casio recommends performing a full initialization (SHIFT, 9, Initialize All, Yes) to ensure the calculator starts cleanly.