Reverse Calculator

What Is Your Ad Budget Ceiling?

With $12,000 revenue at 50% margin ($6,000 gross profit) and a $3,000 profit goal, your max ad spend is $3,000. Spend more and you miss the goal; at break-even you could spend the full $6,000 but keep nothing. A 20%-of-gross-profit discipline caps spend at $4,800.

Results

Visualization

Cashbizly provides illustrative business estimates only. Results depend on your inputs and assumptions and are not accounting, tax, or legal advice. Consult a CPA or financial advisor before major decisions. Tax-year figures (mileage, QBI, SEP, etc.) are labelled by year and should be verified at IRS.gov.

How It Works

Max Spend = Revenue x Margin% - Target Profit. It is the reverse of the marketing-ROI equation: solve for the spend that leaves your desired profit. The break-even spend is simply the gross profit. Keep a margin of safety — attribution error means real spend should sit below the ceiling.

What Should You Do?

Scenario 1: raising margin to 60% lifts max spend to $4,200 for the same goal. Scenario 2: a $5k goal on $6k gross profit leaves only $1k for ads. Scenario 3: if revenue is over-attributed, the real ceiling is lower — be conservative.

Frequently Asked Questions

Why keep a safety margin?

Attribution overstates revenue; spending to the mathematical ceiling risks actual losses.

Margin or revenue?

Use margin-adjusted gross profit; revenue-based limits ignore cost of goods.

How does this pair with CAC?

Both set spending ceilings; CAC is per-customer, this is per-campaign. See our CAC tool.

Authoritative References

Investopedia — Marketing ROI — Profit and spend relationship.
FTC — Ad Substantiation — Truthful marketing claims.