Profitlee glossary

Amazon FBA & TikTok Shop seller glossary

Plain-English definitions for every fee, metric, and acronym a new seller meets on Amazon FBA or TikTok Shop. Use these to make sense of the calculator's inputs and outputs — or skim the whole vocabulary before you start sourcing.

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Fulfillment modes

Who actually picks, packs, and ships the order — and the trade-off between fees and control.

FBA — Fulfilled by Amazon: You send inventory to Amazon's warehouses; they pick, pack, and ship every order.; Higher per-unit fees, but you get Prime eligibility, Amazon's logistics, and customer-service handling. Best when shipping volume is too high to handle in-house.
FBM — Fulfilled by Merchant: You ship every order yourself or via your own 3PL.; Lower per-unit fees and no FBA cost, but you handle Prime requirements, customer service, and returns alone. Good for bulky items where FBA fees would eat the margin.
FBT — Fulfilled by TikTok: TikTok Shop's version of FBA — they warehouse, pack, and ship your orders.; One bundled all-in fee (no separate weight tiers like Amazon), plus a $3-per-order charge on returns. First 60 days of storage are free.
Self-fulfilled: You ship every TikTok Shop order yourself.; TikTok still takes the 6% commission but none of the logistics cost. You provide your own pick/pack rate, outbound shipping cost, and 3PL storage rate.

Physical & supply inputs

What you pay your supplier and how the platform measures your product before any fees kick in.

FOB price: Per-unit cost charged by your supplier, ex-factory (before any shipping).; "FOB" stands for Free On Board — you take ownership when the goods leave the supplier's port. This is the raw factory cost, not your final landed cost.
Head shipping: Per-unit cost to ship inventory from your supplier to Amazon's / TikTok's warehouse.; Usually sea freight + import handling + first-mile trucking rolled into one. Divide your container total by units inside to get this. Often the biggest hidden cost for new sellers.
Duty (per unit): Per-unit import tariff in your listing currency — NOT a percentage. If your tariff rate is 12% and FOB is $3.50, enter $0.42.; Section 301 (US-China) tariffs alone can add 25% or more. Use your product's HTS code to look up the rate, then multiply by FOB to get the per-unit amount. Ignoring duty is the most common way newcomers overstate their margin.
Unit weight: The product's physical weight, packaged and ready to ship.; One of two inputs that drive fulfillment fees. If your dimensions are big and the product is light, the dim weight (volumetric) wins instead — see Ship weight.
Dim weight (dimensional weight): Volumetric weight: L × W × H ÷ a fixed divisor (139 for US inches/lb).; Amazon and TikTok bill fees on whichever is HIGHER — physical weight OR dim weight. Bulky-but-light products (laundry baskets, pillows, foam) almost always pay on dim weight.
Ship weight: The weight the platform actually bills on — max(unit weight, dim weight), rounded up.; Drives your fulfillment-fee tier. When dim wins (oversized but light product), the value shows '(dim)' to flag that you're paying on volume, not mass.
Size tier: Amazon's classification of your product based on dimensions and ship weight.; Drives the FBA fulfillment fee table you fall into. Small Standard < Large Standard < Small Bulky < Large Bulky < Extra-Large ascending in price. TikTok doesn't use size tiers.

Amazon FBA specifics

Settings that only matter when Amazon is doing your fulfillment — placement, storage, and season.

Inbound placement: How Amazon distributes your inventory across their warehouse network. US Amazon FBA only — DE bundles inbound into Pan-EU, JP has a single FC.; "Optimized" ships to 5+ FCs as Amazon directs and is FREE. "Single" (Minimal Shipment Splits) ships to one FC — highest per-unit fee, ranging $0.23–$6.00 depending on size tier and ship weight. "Partial" ships to 2–3 FCs at a mid-tier fee, but Amazon removed this option for Standard-size items in Feb 2025 — only Bulky items can pick it today. Extra-Large pays no inbound fee on any option.
Storage months: How many months you expect your stock to sit in the warehouse before selling through.; Storage is billed monthly per cubic foot. The longer inventory sits, the more you pay. New sellers commonly underestimate this — assume slower sell-through until you have real data.
Storage season: Amazon has two storage-rate seasons: Jan-Sep at the base rate, Oct-Dec at the peak rate.; Q4 holiday demand makes warehouse space scarce, so Amazon roughly triples storage fees in Oct-Dec. Plan re-stocks accordingly to avoid Q4 carry.
Storage months past 60-day free window: How many months your TikTok FBT inventory will sit AFTER the first 60 days (which are free).; TikTok gives 60 days of free storage in their warehouses. Past that, it's $0.50/cu ft/month. Most fast-moving products never hit this cost.

Cost stack

Every per-unit charge that lands on your P&L between the supplier dock and the customer's doorstep.

Landed COGS: Total per-unit cost to get the product into the warehouse: FOB + head shipping + duty.; COGS = Cost of Goods Sold. "Landed" means all the way to the warehouse door, not just the factory dock. This is your true cost basis — sellers who only count FOB wildly overestimate their margin.
Inbound fee: Amazon's charge for placing your inventory across their warehouses (FBA only).; Depends on the Inbound placement option you chose. Zero on FBM and on TikTok — those modes don't use Amazon's warehouse network.
FBA fulfillment fee: Per-unit fee Amazon charges to pick, pack, and ship the order.; Driven by your size tier and ship weight. Amazon updates the rate card annually and sometimes mid-year. The US version bakes in a 3.5% fuel surcharge.
Fuel surcharge: A 3.5% multiplier Amazon US adds on top of fulfillment fees (current rate).; Amazon updates this monthly. It has bounced between 2.5% and 5% in recent years. Check Seller Central for the current rate before committing to long-term cost forecasts.
Referral fee: The percentage of your sale price the platform keeps as a marketplace commission.; Amazon: varies 8-45% by category, with a $0.30 per-unit minimum. TikTok: flat 6% for most categories, 5% for select jewelry. This is usually your single biggest fee line.
Commission (referral fee): TikTok Shop's name for the marketplace commission on each sale.; Flat 6% on most categories, 5% on select jewelry sub-types. No per-unit minimum unlike Amazon. Built into TikTok's payout — you receive sale price minus this commission.
Storage fee: What the platform charges to hold your inventory in their warehouse.; Amazon US: $0.78/cu ft (Jan-Sep) or $2.40 (Oct-Dec) per month, per cubic foot. TikTok FBT: free for 60 days, then $0.50/cu ft. Becomes painful for slow-moving SKUs.
Total cost (per unit): The sum of every fee + your landed COGS for one unit.; Includes COGS, fulfillment, referral, storage, and any platform-specific fees (inbound, fuel surcharge, return handling). Your gross profit is sale price minus this number.

Revenue & marketing

Pricing, advertising, returns — the levers that determine how much you actually take home.

Sale price: What customers pay before any shipping or tax.; The listing price you set, not Amazon's suggested price. Includes any built-in shipping if you offer free Prime shipping.
PPC ACoS — Advertising Cost of Sale: Ad spend as a percentage of ad-attributed sales. ACoS 30% means $30 in ads per $100 of ad-driven revenue.; Lower is better. Most categories sit at 15-35%. If your ACoS is higher than your profit margin, you're paying to lose money on every ad sale.
ROAS — Return on Ad Spend: The inverse of ACoS: how many dollars you net for every $1 in ad spend.; 3.0x or higher is healthy. Under 1.0x means ads are unprofitable. Many sellers find ROAS easier to reason about than ACoS — bigger number is better.
Return rate: Percentage of sold units that customers send back.; Apparel ~25%, electronics ~10%, home & kitchen ~5%. Returns destroy margin twice: lost sale + return shipping/handling. Worth modeling honestly.
Return loss / unit: Estimated loss per unit from returns, baked into the cost stack.; Roughly price × return rate, plus any platform fees that don't refund. For TikTok FBT, includes the $3-per-order return handling fee.
Referral category: The category the platform uses to pick your referral fee rate.; Picking the wrong category can mean paying 15% when you should be paying 8%. Verify against the platform's official category guidelines before committing to your fee math.
Monthly volume: Units you expect to sell per month.; Used to extrapolate the per-unit cost stack into a monthly P&L. Sandbag this number — overestimating volume turns 6-month inventory into 18-month dead stock.
Units per case: Case pack or master pack size from your supplier.; Optional input. When set, the calculator shows profit-per-case so you can think about cash flow in shipment-sized chunks instead of single-unit math.

Outputs & metrics

What the calculator gives you back — and how to read each number.

Gross profit (per unit): Sale price minus total cost. Excludes PPC and returns.; "Gross" is the ceiling. Real take-home ("net profit") is always lower once you factor in advertising and returns.
Gross margin: Gross profit as a percentage of sale price.; Rule of thumb: 30%+ is healthy, 40%+ is great, sub-20% leaves no room for ads or price competition.
Net profit (after PPC + returns): Gross profit minus PPC spend per unit minus return loss per unit.; This is your actual take-home per unit. The number that matters for sourcing decisions and pricing.
Net margin: Net profit as a percentage of sale price.; What's left after every cost the calculator can model. Healthy SKUs land at 15-25%+ net; tighter than that and small fee changes can flip you to a loss.
Break-even price: The lowest sale price at which net profit equals $0, holding everything else constant.; Useful for negotiating with suppliers ("if I can't sell above $X, this product is dead") and for setting promotional floors. Uses the effective referral rate at the current price.
Break-even monthly volume: Units per month needed to cover monthly storage cost at the current per-unit margin.; Below this volume, storage eats your unit profit. Above it, every extra unit is pure margin. Only meaningful when you have positive per-unit net profit.
Monthly P&L: Profit-and-loss extrapolation: per-unit cost stack × monthly volume.; Quick sanity check on whether the SKU is worth your time. A product with 20% net margin but 50 units/month is a side project; 20% margin at 5,000/month is a real business.
Margin tier badge: Color-coded label that summarises a margin: Banger 🔥 ≥40%, Healthy ❤️ 30-40%, Caution ⚠️ <30%.; Visual shorthand. A Banger product can absorb price competition and ACoS hikes; a Caution product can't.