Percent change between two numbers
Find how much a value rose or fell, as a percentage of where it started.
Percent change = (new - old) ÷ old × 100. From 80 to 100 the change is 20, which is 25% of 80. From 100 to 80 it is a 20% drop, not 25%, because the starting value is different.
Classic Graphing 84
Start on the main screen: Press 2nd then mode (QUIT) to get back to the home screen. Pressing clear on a menu also backs out of it.
Type (new - old) ÷ old × 100.
(100−80)÷80×100enter
You should see25
Natural Scientific 991
Start on the main screen: Press MENU, then 1 (Calculate) to return to the main calculation screen. AC clears the line you are on.
Type the same formula and press equals.
(100−80)÷80×100=
You should see25
Classic Financial II
Start on the main screen: Press 2ND then CPT (QUIT) to leave a worksheet and return to the plain calculator. ON/OFF also drops back to the standard screen and clears an error.
Open the percent-change worksheet (2nd, 1). OLD is the first line: type 80 and press enter.
2ND%CH180ENTERMove down to NEW, type 100 and press enter, then CPT.
↓100ENTER↓CPT
You should see%CH= 25.00
RPN Financial 12
Start on the main screen: There is no menu to leave: the display always shows the X register. Press f then R/S (P/R) to leave program mode, and clear a pending prefix by pressing ON.
Put the old value first, then ENTER, then the new value.
80ENTER100Press the Δ% key. It compares the new value (on the display) with the old one just above it.
Δ%
You should see25.00
The Δ% key needs no prefix. Its shifted partner on this model is SOYD, used for depreciation.
Tips
- A drop of 20% followed by a rise of 20% does not get you back to the start. The base changes each time.