Calculation type: Finding the original value before a percentage increase (removing the tip).
Calculator usage: Use the
Original Before Increase Calculator (“What was the Original value before an Increase % resulted in the New value?”). Enter
15 [B] and $
69 [C]. The calculator will find the bill before the tip.
Watch out: You cannot simply subtract
15% from the total. $
69 − (
15 /
100) × $
69 = $
58.65 is NOT correct, because the tip was added to the bill before the tip, not to the total.
Formula explanation:
We want to find the bill before the tip, when the total of $
69
already includes a
15% tip.
Formula: Bill before tip = Total / (1 + Tip rate / 100)
Bill before tip = $
69 / (1 +
15 / 100) = $
69 /
1.15 = $
60
Tip amount = $
69 − $
60 = $
9