Amazon Fba Calculator

Amazon FBA profit calculator. Input product price, COGS, dimensions, weight, and ad spend — get true net profit, margin, ROI, and break-even ACoS. Triggers:...

Security Scan

The skill's content matches an Amazon FBA calculator, but its runtime instructions reference a CLI and allow Bash execution while the package declares no install, no required binaries, and provides no code — this mismatch is unexplained and warrants caution.

Purpose & Capability

Name, description, and SKILL.md content all describe an FBA profit calculator and include formulas, fee tables, metrics, and rules consistent with that purpose.

Instruction Scope

The SKILL.md lists CLI commands (e.g., `fba calc`, `fba fees`, `fba save`) and sets allowed-tools: Bash, implying it expects to run a local CLI. However the skill provides no code, no install, and no declared required binaries — it's unclear how those commands are satisfied. allowed-tools: Bash also means the agent could run arbitrary shell commands at runtime; while the instructions themselves remain focused on calculations, this tool permission combined with the missing CLI is an unexplained risk.

Install Mechanism

There is no install spec and no code files (instruction-only). That is low-risk from supply-chain perspective, but it creates a functional mismatch because the SKILL.md documents a CLI without declaring or installing it. The author may have intended to document a separate CLI repository (homepage provided) but did not link an install step.

Credentials

The skill declares no required environment variables, no credentials, and no config paths. This aligns with a local calculator that doesn't need external secrets.

Persistence & Privilege

No elevated privileges or always:true present. The skill is user-invokable and allows model invocation (normal). It doesn't request persistent system-level presence.

What to consider before installing

This skill appears to be a legitimate FBA profit calculator, but there is a notable mismatch: the runtime instructions show a CLI (`fba ...`) and permit running Bash, yet the skill bundle includes no code and no install instructions. Before installing or enabling this skill you should: 1) Verify the linked GitHub repo (https://github.com/mguozhen/amazon-fba-calculator) to confirm whether a separate CLI exists and how to install it from a trusted source; 2) Be aware that allowed-tools: Bash grants the agent the ability to run shell commands — confirm what commands it will run or restrict the Bash tool if you don't want remote shell execution; 3) If you expect a purely conversational calculator (no external binary), ask the author to remove CLI examples or provide an inline implementation in SKILL.md; 4) If you plan to install a third-party CLI, prefer installing from official releases (GitHub releases, package manager) and audit the binary/source code before granting the agent permission to execute it. If you can't confirm the origin of the CLI or the expected commands, consider treating the skill as untrusted.

Amazon FBA Profit Calculator

Calculate true net profit for any Amazon product — accounting for all fees, costs, and ad spend. Know your real margin before you source.

Commands

fba calc                        # interactive profit calculation
fba calc [price] [cogs] [weight]  # quick calculation with known values
fba fees                        # show current FBA fee schedule
fba break-even                  # calculate break-even ACoS
fba compare [price1] [price2]   # compare two price points
fba save [product-name]         # save product profile
fba history                     # show saved products

What Data to Provide

• Sale price — your selling price on Amazon
• COGS — product cost + freight to Amazon warehouse
• Dimensions & weight — for FBA fulfillment fee calculation
• Category — for referral fee %
• Ad spend / ACoS — optional, for true profit with PPC
• Other costs — prep fees, photography, samples

No API keys needed. Works from verbal descriptions or exact numbers.

Fee Structure (2024–2025)

Amazon Referral Fees by Category

Category	Referral Fee
Most categories	15%
Electronics	8%
Clothing & Accessories	17%
Jewelry	20% (up to $250)
Books, Music, Video	15%
Computers	8%
Furniture	15% (+ $30 min)
Automotive	12%

FBA Fulfillment Fees (2025 US)

Size Tier	Weight	Fee
Small Standard	≤4 oz	$3.06
Small Standard	4–8 oz	$3.15
Small Standard	8–12 oz	$3.24
Large Standard	≤4 oz	$3.68
Large Standard	1 lb	$4.51
Large Standard	2 lb	$5.22
Large Standard	+1 lb	+$0.38/lb
Large Bulky	up to 50 lb	$9.73 + $0.42/lb over 1lb

Additional Fees to Include

• FBA Storage: $0.78/cubic foot/month (Jan–Sep), $2.40 (Oct–Dec)
• Monthly Storage: estimate based on sell-through rate
• Prep/Labeling: $0.55/unit (Amazon prep service)
• Returns: ~2–5% of revenue depending on category

Calculation Formula

Gross Revenue       = Sale Price
- Referral Fee      = Sale Price × Referral %
- FBA Fee           = Based on size/weight tier
- COGS              = Product cost + inbound freight
- PPC Cost          = Sale Price × ACoS
- Storage           = (Units/month × cubic feet × rate) / units sold
- Other Costs       = Prep + photography amortized
─────────────────────────────────────
Net Profit          = Revenue - All costs above
Net Margin %        = Net Profit / Sale Price × 100
ROI                 = Net Profit / COGS × 100
Break-even ACoS     = Net Margin % (before PPC)

Output Format

Every calculation outputs:

1. P&L Table — line-by-line cost breakdown
2. Key Metrics — Net Profit / Margin / ROI / Break-even ACoS
3. Sensitivity Analysis — profit at ±10%, ±20% price changes
4. Risk Flags — margin below 15%, storage risk, high referral fee categories
5. Optimization Tips — specific suggestions to improve margin

Rules

1. Always show full fee breakdown — never hide line items
2. Flag when margin is below 15% (risky for Amazon sellers)
3. Include seasonal storage surcharge warning for Q4
4. Show both pre-PPC and post-PPC margins
5. Ask for category if not provided — referral fee varies significantly
6. Note when estimated values are used vs. exact inputs

Benchmarks

Metric	Healthy	Warning	Danger
Net Margin	>25%	15–25%	<15%
ROI	>50%	30–50%	<30%
Break-even ACoS	>25%	15–25%	<15%
Storage/Revenue	<3%	3–8%	>8%