Car Wash: Washes to Justify a Membership

Excel Formulas › Car Wash & Detailing

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Members ask, and so should you: how many washes a month make the unlimited plan worth it? Divide the monthly price by a single wash and round up.


Quick formula: Monthly price divided by a single wash, rounded up:
=ROUNDUP(B2/C2,0)

A $30 plan against a $12 single wash pays off at 3 washes a month — the simple pitch for the membership.

Functions used (tap for the full reference guide):

The example

Three plans, each with a monthly price and the price of a single wash.

ABCD
1PlanMonthly $Single wash $Washes to justify
2Basic unlimited$30$123
3Deluxe unlimited$45$183
4Premium unlimited$60$223

The formula

Round up so the member clears the cost:

=ROUNDUP(B2/C2,0) // monthly price / single wash, round up

How it works

The break-even is just a division you round up:

  1. B2 is the monthly membership price.
  2. C2 is what one wash would cost without the plan.
  3. Dividing gives the exact break-even; ROUNDUP moves it to the next whole wash, the point where the member comes out ahead.

Use this in your sign-up pitch: "Wash three times a month or more and the plan pays for itself."

Try it: interactive demo

Interactive

Enter the monthly price and the single-wash price.

Variations

Yearly plan

Compare an annual membership against single washes over the year.

=ROUNDUP(AnnualPrice/SingleWash,0)

Pitfalls & errors

Round up: at the exact break-even, the member needs one more wash to truly come out ahead.

Compare like wash tiers — a deluxe membership against a basic single wash makes the plan look better than it is.

Practice workbook

📊
Download the free Car Wash: Washes to Justify a Membership practice workbook
Edit the yellow Monthly and Single wash cells; the Washes column rounds up.

Frequently asked questions

Why round up instead of down?
At the exact break-even the member only matches the cost. Rounding up shows the first wash count where the plan truly saves them money.
Does this account for time saved?
No — it is a pure dollar break-even. The convenience of unlimited washes is extra value on top of this number.

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Function references: ROUNDUP