Calculate the percent increase or decrease from an old value to a new one.
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=(B2-A2)/A2Subtract the old value from the new value, then divide by the old value. Format as Percentage. A positive result is growth; a negative result is a decline.
=(150-120)/120→25%Sales grew 25% from 120 to 150.
=(80-100)/100→-20%A drop from 100 to 80 is a 20% decrease.
=150/120-1→25%The same calculation written more briefly: new value divided by old value, minus 1.
Guard against divide-by-zero
=IF(A2=0, "", (B2-A2)/A2)Returns blank when the old value is 0.
Apply a custom number format like +0.0%;-0.0% to force the sign.
Always the old (starting) value. Dividing by the new value gives a different, incorrect percentage.
Divide by the absolute value: =(B2-A2)/ABS(A2). Otherwise the sign of the result is reversed.
The cell is formatted as a number. Select it and apply the Percentage format (Ctrl+Shift+%).
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