iPhone Calculator history helps when you need a number from an earlier calculation. Instead of entering everything again, you can review the expression and reuse its result.
Open a previous calculation
In Calculator, use the mode control to choose Basic or Scientific. Tap the clock-shaped history button. Tap an entry to reload it, or touch and hold an entry to choose Copy Expression or Copy Result.
The controls can vary with your iOS version. These directions refer to the interface in Apple’s current guide; if your Calculator looks different, check the available mode and history controls before following a remembered button position.
Check the expression before copying
A result alone can be ambiguous. Before copying, read the numbers and operation that produced it. This matters when you have made several similar calculations, such as totals for different groups of items.
For practice, calculate a simple total from a few quantities, perform a second unrelated calculation, then return to the first entry. Copy its result into a note and add a label explaining what it represents.
Choose expression or result deliberately
Copying the expression is useful when you want to review your method. Copying the result is convenient when you only need the answer in another document. In either case, add any relevant unit yourself so the number remains understandable outside Calculator.
Keep important calculations elsewhere
- Record the purpose of a number beside it.
- Check decimal placement before reuse.
- Keep supporting quantities with important totals.
- Do not treat a history entry as a permanent record.
History reduces repeated typing, but it cannot determine whether you entered the right quantities. A quick review of the original expression remains the most useful final check.
Official reference: Read the official instructions.
Featured image: conceptual illustration, not a device screenshot.