How FBA Calcs computes every figure, where the data comes from, and how the numbers are kept current. No black box — every formula below is the exact logic running in the tool.
Referral = max(price × categoryRate(price), categoryMinimum)
Category rates are tiered at the official boundaries: beauty and baby 8% at or below $10 (15% above), clothing 5% ≤ $15 / 10% $15.01–20 / 17% above $20, consumer electronics 8%, grocery 8% ≤ $15 (15% above), jewelry 20% ≤ $250 (5% above), furniture 15% ≤ $200 (10% above), full-size appliances 8%, media 15% + $1.80 closing fee. Most other categories are 15%.
Fulfillment = official 2026 band rate for the billable weight
Billable weight = the greater of actual weight and dimensional weight (section 1.3). US small-standard odd ounces round up to the next even tier (e.g. 7 oz → 8 oz). Large-standard bands, bulky and oversize tiers follow the official 2026 rate card; the 3–20 lb formula is $6.15–$7.23 plus $0.16 per half-pound above 3 lb (non-peak).
US: (L × W × H inches) ÷ 139 · International: (L × W × H cm) ÷ 5000
FBA charges the greater of actual and dimensional weight. The tool highlights when dimensional weight drives the fee and estimates packaging savings: saved per unit = (fulfillment at actual weight) − (fulfillment at billable weight).
Fuel = 3.5% × fulfillment fee (US, effective Apr 17, 2026)
Applied to the fulfillment fee, not the sale price. Amazon's official estimate puts the average US impact at about $0.17 per unit. The surcharge toggle is off automatically for non-US marketplaces (manual fee mode).
Storage per unit = monthlyRatePerFt³ × (L×W×H ÷ 1728) × storageDays ÷ 30
Official 2026 US rates: $0.78 per ft³ standard (Jan–Sep), $2.40 peak (Oct–Dec) for standard-size; $0.56 / $1.40 for oversized. Storage days default to 0 in Quick mode — sellers storing 60+ days should enter their real average.
Return amortization = returnRate × (referral + fulfillment + fuel + returnFee + landed cost)
Important nuance: Amazon's official US return model charges a per-item return processing fee above a category-specific return-rate threshold, not a blanket amortization. FBA Calcs amortizes by default because it is the conservative "expected cost per unit sold" view, and lets you enter your actual per-item return fee in Advanced costs. For high-return categories (apparel 20–30%), entering the real per-item fee (e.g. $2.08 apparel return processing above threshold) gives the closest-to-official figure. Our amortized model is deliberately slightly conservative so profit is never overstated.
Placement = official per-unit fee for the "minimal splits" option, applied only when that option is selected
The Amazon-optimized split option carries no placement fee and is the default. Fee is banded by billable weight and size tier, computed from the midpoint of Amazon's official 2026 range.
Advertising = price × ACoS% · Other = flat per-unit amount
Net = price − landedCost − all fees above · Margin = net ÷ price × 100
Break-even price = binary search over candidate prices (60 iterations, precision $0.01) until net ≈ 0, re-deriving referral and fulfillment tier boundaries at every candidate so the answer is exact across threshold crossings.
| Date | Change | Tool status |
|---|---|---|
| 2026-01-15 | 2026 US fulfillment rate card effective (avg +$0.08/unit) | Built in as the 2026 non-peak card |
| 2026-04-17 | US fuel & logistics surcharge 3.5% (avg ≈ $0.17/unit) | Built in, toggle on by default |
| 2026-10-15 | Peak holiday window opens (until 2027-01-14, avg ≈ $0.32/unit) | Shown in fee editor; not auto-applied |
| 2026-10-27 | Rate card re-verified against Seller Central; methodology page published | Trust badge month updated |
| 2026-11-02 | EU/UK fuel & logistics surcharge rises 1.5% → 2% (UK, DE, FR, IT, ES, PL, SE, NL, IE, BE) | Manual fee mode — enter 2% surcharge in your marketplace's rate |
Every figure here is an estimate built from Amazon's published schedules. Before you commit inventory, confirm the fee preview in your Amazon Seller Central account — actual charges can differ (returns, removals, discontinuations, promotions).
Open the FBA Profit Calculator →Accuracy depends on the rate card and the cost buckets covered. FBA Calcs uses Amazon's official 2026 US fee schedule, adds fuel surcharge, inbound freight, storage, returns and placement, and lets you override any fee. It is an estimate — Amazon's fee preview in Seller Central is the authoritative check before you price a product.
Net profit per unit = selling price − referral fee − FBA fulfillment fee − fuel & logistics surcharge − advertising − other fees − inbound freight per unit − return amortization − storage − placement − item cost.
Billable weight = the greater of actual weight and dimensional weight. US (inches/lb): (L × W × H) ÷ 139. International (cm/kg): (L × W × H) ÷ 5000. Odd ounces round up to the next even tier in the US small-standard schedule.
FBA Calcs amortizes returns per unit: return rate × (referral + fulfillment + surcharge + return fee + landed cost). Amazon's official US model charges a per-item return processing fee above a category return-rate threshold — so for high-return categories (apparel 20–30%), enter your actual per-item return fee in the Advanced costs panel for a precise estimate.
The built-in card covers Amazon's official 2026 non-peak US schedule (Jan 15 – Oct 14, 2026), the 3.5% fuel & logistics surcharge effective Apr 17 2026, and the Oct 15 2026 – Jan 14 2027 peak window (shown in the fee editor, not auto-applied). Storage uses $0.78 per ft³ standard / $2.40 peak. Non-US marketplaces use manual fee entry.