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ROAS & Break-Even Ad Spend Calculator

See the exact CAC, CPC, ROAS, and ACoS your offer can support before paid traffic starts eating your margin.

Where this fits

📦 Business & Seller Ops Seller OS Employees Sellers

This tool lives inside Seller OS and is most useful for employees and sellers.

Corp Tax Rate21%(federal flat rate)

SE Threshold$400(net earnings floor)

FICA Cap 2024$168,600(SS wage base)

ROAS & Break-Even Ad Calculator — Know the exact CPC, CAC, ROAS, and ACoS your offer can support before you burn money on traffic.

Offer Economics

Sale price

COGSProduct cost per order

Fulfillment costShipping, pick-pack, or delivery

Fees & Returns

Platform feeAmazon referral, marketplace fee, or channel take

Payment feeCheckout processor %

Flat processor feeUsually $0.30 style fee

Return rateExpected refunded orders

Traffic Inputs

Conversion rateClicks that become orders

Current CPCAverage cost per click

Contribution before ads

$15.63

Maximum room for acquisition spend

Current CAC

$17.74

from $1.10 CPC at 6.2%

Profit after ads

-$2.11

-5.3% net margin

Break-even ROAS

2.56x

2.25x now vs 2.56x break-even

Break-even ACoS

39.1%

Ad spend as % of sales ceiling

Max CPC

$0.97

Gap vs current CPC: -$0.13

The underlying offer works, but the current traffic cost is too high for the margin you have. You need better conversion or cheaper clicks before scaling.

Seller Growth Playbook

Ads only work when the order economics support them.

This calculator turns your margin stack into hard traffic ceilings, so you can stop guessing whether Amazon PPC, Meta ads, or Google Shopping are helping or hurting.

What To Do Next

You can afford up to $15.63 to acquire an order before profit goes to zero. Use that as your hard ceiling.

Your current CPC is $0.13 above the break-even ceiling. Push for better creative, relevance, or landing-page conversion before spending harder.

Run the product through your full seller P&L next so your ad math, fees, and cash-flow plan all line up before you scale.

Max CAC

$15.63

Your highest survivable acquisition cost per order.

Current CAC gap

-$2.11

How far current acquisition cost sits from the break-even ceiling.

Break-even ROAS

2.56x

Minimum return on ad spend needed to avoid losing money.

Current margin

-5.3%

Net margin after modeled traffic costs.

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Revenue per order

sale_price

$39.99

= $39.99

This is the gross revenue created when one order converts.

Unit economics revenue input

Platform fee

sale_price × platform_fee_%

$39.99 × 15.0%

= $6.00

Amazon referral fees, marketplace commissions, or channel take-rates come out before ads get paid back.

Marketplace take-rate formula

Payment processing fee

sale_price × processor_% + flat_fee

$39.99 × 2.9% + $0.30

= $1.46

This captures checkout processor drag like Shopify Payments, Stripe, or other card fees.

Card processing fee formula

Expected return loss

(COGS + fulfillment_cost) × return_rate

($11.00 + $5.25) × 4.0%

= $0.65

Returns do not hit every order, so we blend the expected loss across all orders using the return rate.

Expected-value loss formula

Contribution before ads

sale_price − COGS − fulfillment − platform_fee − payment_fee − return_loss

$39.99 − $11.00 − $5.25 − $6.00 − $1.46 − $0.65

= $15.63

This is the most you can afford to pay to acquire one order before your net profit hits zero.

Contribution margin before acquisition spend

Current CAC from CPC and conversion rate

CPC ÷ conversion_rate_decimal

$1.10 ÷ 0.0620

= $17.74

If you pay this click cost and convert at this rate, this is your blended cost to acquire one order.

Customer acquisition cost identity

Profit after ads

contribution_before_ads − current_CAC

$15.63 − $17.74

= -$2.11 (-5.3% margin)

Your current traffic math is underwater. Either lift conversion, lower CPC, or rebuild margin before scaling.

Per-order profit after acquisition spend

Break-even ROAS

sale_price ÷ max_CAC

$39.99 ÷ $15.63

= 2.56x

ROAS tells you how many dollars of revenue you need back for each dollar of ad spend just to avoid losing money.

ROAS break-even formula

Break-even ACoS

max_CAC ÷ sale_price

$15.63 ÷ $39.99

= 39.1%

ACoS is the mirror image of ROAS and is especially useful for Amazon PPC. Anything above this threshold burns profit.

Amazon ACoS identity = ad spend ÷ sales

Max CPC at current conversion rate

max_CAC × conversion_rate_decimal

$15.63 × 0.0620

= $0.97

This is the ceiling you can pay per click at the current conversion rate before the economics stop working.

CPC ceiling from CAC and conversion rate

Key insight

At the current conversion rate, your offer can only support about $0.97 per click before profit disappears.

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