Worked example: two similar items in one parcel
Last updated: 2026-07-31
Written and reviewed by Seller Profit Guard Editorial Team.
Two USD 25 items plus USD 10 buyer shipping create USD 60 gross buyer amount. After USD 16 direct item cost, USD 6 postage, USD 1 packaging, USD 2 handling, and USD 6.30 modeled fees, combined-order contribution is USD 28.70.
Freeze the two synthetic items
Reproduce control 1: Use one unit in each group at USD 25 price, USD 8 direct cost, and 1.5 pounds product weight. This worked-example role preserves an ordered monetary and physical ledger so every displayed result can be recalculated. Save source state, full-precision value, display value, currency or physical unit, order state, package state, reviewer, and review date.
Test the closest passing boundary and closest failure. State how a mismatch changes a line-by-line similar-item consolidation result, which evidence resolves it, who owns correction, and whether the packet must be blocked, reviewed, limited, superseded, or restored.
Freeze the parcel
Reproduce control 2: Use 3.5 pounds finished weight and 12 × 10 × 6 inches under one synthetic service pattern. This worked-example role preserves an ordered monetary and physical ledger so every displayed result can be recalculated. Save source state, full-precision value, display value, currency or physical unit, order state, package state, reviewer, and review date.
Test the closest passing boundary and closest failure. State how a mismatch changes a line-by-line similar-item consolidation result, which evidence resolves it, who owns correction, and whether the packet must be blocked, reviewed, limited, superseded, or restored.
Extend merchandise lines
Reproduce control 3: Calculate USD 25 plus USD 25 and retain USD 50 merchandise revenue. This worked-example role preserves an ordered monetary and physical ledger so every displayed result can be recalculated. Save source state, full-precision value, display value, currency or physical unit, order state, package state, reviewer, and review date.
Test the closest passing boundary and closest failure. State how a mismatch changes a line-by-line similar-item consolidation result, which evidence resolves it, who owns correction, and whether the packet must be blocked, reviewed, limited, superseded, or restored.
Add buyer shipping
Reproduce control 4: Add the literal USD 10 collected for the combined order to reach USD 60 gross buyer amount. This worked-example role preserves an ordered monetary and physical ledger so every displayed result can be recalculated. Save source state, full-precision value, display value, currency or physical unit, order state, package state, reviewer, and review date.
Test the closest passing boundary and closest failure. State how a mismatch changes a line-by-line similar-item consolidation result, which evidence resolves it, who owns correction, and whether the packet must be blocked, reviewed, limited, superseded, or restored.
Extend the fee convention
Reproduce control 5: Apply 10% to USD 60 and add USD 0.30 to produce USD 6.30 modeled fees. This worked-example role preserves an ordered monetary and physical ledger so every displayed result can be recalculated. Save source state, full-precision value, display value, currency or physical unit, order state, package state, reviewer, and review date.
Test the closest passing boundary and closest failure. State how a mismatch changes a line-by-line similar-item consolidation result, which evidence resolves it, who owns correction, and whether the packet must be blocked, reviewed, limited, superseded, or restored.
Subtract combined costs
Reproduce control 6: Subtract USD 16 item cost, USD 6 postage, USD 1 package, USD 2 handling, and USD 6.30 fees. This worked-example role preserves an ordered monetary and physical ledger so every displayed result can be recalculated. Save source state, full-precision value, display value, currency or physical unit, order state, package state, reviewer, and review date.
Test the closest passing boundary and closest failure. State how a mismatch changes a line-by-line similar-item consolidation result, which evidence resolves it, who owns correction, and whether the packet must be blocked, reviewed, limited, superseded, or restored.
Compare separate postage
Reproduce control 7: Subtract USD 6 combined postage from USD 12 comparable separate postage to show USD 6 savings. This worked-example role preserves an ordered monetary and physical ledger so every displayed result can be recalculated. Save source state, full-precision value, display value, currency or physical unit, order state, package state, reviewer, and review date.
Test the closest passing boundary and closest failure. State how a mismatch changes a line-by-line similar-item consolidation result, which evidence resolves it, who owns correction, and whether the packet must be blocked, reviewed, limited, superseded, or restored.
Read the decision
Reproduce control 8: Confirm USD 28.70 contribution clears a USD 20 target while shipping-side contribution equals zero. This worked-example role preserves an ordered monetary and physical ledger so every displayed result can be recalculated. Save source state, full-precision value, display value, currency or physical unit, order state, package state, reviewer, and review date.
Test the closest passing boundary and closest failure. State how a mismatch changes a line-by-line similar-item consolidation result, which evidence resolves it, who owns correction, and whether the packet must be blocked, reviewed, limited, superseded, or restored.
Use the two-similar-item calculation ledger at one combined-order grain
Open the calculator after the two-similar-item calculation ledger identifies seller alias, two item-group aliases, whole quantities, prices, direct costs, product weights, finished parcel, buyer shipping, final postage, qualified separate-postage comparison, package and handling allocations, fee convention, three seller thresholds, real source-review date, nine evidence confirmations, currency, units, month, scope, and unresolved issues. Use only synthetic or aggregate values publicly.
Save merchandise revenue, gross buyer amount, direct cost, percentage and fixed fees, contribution, margin, per-unit result, shipping-side contribution, postage savings and rate, target headroom, summed item weight, package weight allowance and share, thresholds, confirmations, decision, and issues. Preserve the prior packet whenever evidence changes.
Apply evidence gates before a line-by-line similar-item consolidation result
Block blank, non-finite, nonpositive, fractional-quantity, or structurally invalid evidence; negative costs or target; invalid thresholds, fee percentage, currency, units, source date, month, scope; incomplete confirmations; package weight below item weight; or declared conflicts. A favorable total cannot repair invalid structure.
After structure passes, Review contribution below target, shipping-side funding below zero, postage saving below the seller-entered minimum, or packaging-weight share above the seller-entered maximum. Ready clears only those declared gates and does not certify net profit, carrier price, package acceptance, delivery, demand, or tax treatment.
Separate physical, monetary, and counterfactual changes
Change one item quantity, price, direct cost, product weight, package weight, dimension, buyer charge, postage, package cost, handling cost, fee, separate-postage total, or target at a time. A physical change affects contribution only after evidenced currency costs change.
Record before state, isolated change, group extensions, parcel evidence, cost movement, fee interaction, contribution movement, funding movement, savings movement, decision, confidence, owner, and next evidence action. Do not blend different services or order states into one reassuring average.
Protect buyer, shipment, account, invoice, and raw-order data
Public examples are synthetic. Keep buyer names, addresses, tracking numbers, labels, payment data, credentials, carrier and marketplace account identifiers, negotiated rates, invoices, claims, disputes, messages, and raw exports outside the two-similar-item calculation ledger.
Use aliases, aggregate values, redacted pointers, and access-controlled records. An authorized reviewer should reproduce order grain, parcel identity, arithmetic, comparison, and decision without exposing personal or confidential commercial information.
Release, observe, correct, and restore the combined-shipping asset
Before release, preserve narrow local and remote backups and a rollback identifier. Run typecheck, focused and full tests, integration, build, content and duplicate audits, SEO and static-route validation, mobile and keyboard QA, image and link checks, source review, and local calculator scenarios.
After release, verify status, canonical, indexability, schema, answer blocks, images, hub discovery, strict 404, sitemap policy, events, and production behavior. Record Day 0/7/14/28 evidence and restore the prior version if formula, privacy, accessibility, routing, content, or health regresses.
Build the arithmetic tape
Display group revenue, group cost, group weight, parcel weight, gross amount, fee base, fee result, all costs, contribution, margin, per-unit result, shipping funding, savings, and headroom in order.
Every visible number must have one source line and one formula transition. Do not insert a carrier rate, platform rule, or tax assumption that is absent from the fixture.
Perturb the second item's economics
Change only item-two price, direct cost, or weight across separate runs. Record whether the order target, physical floor, or neither changes.
This identifies which result is monetary and which is physical. Weight does not change contribution until the seller changes evidenced postage or another cost in a new scenario.
Perturb the buyer shipping line
Run USD 0, USD 5, USD 10, and USD 15 while preserving the percentage-fee convention and every cost. Record gross amount, fee, contribution, and shipping-side funding.
Do not call the difference a demand effect or pricing recommendation. It is a deterministic sensitivity family under unchanged order volume and customer behavior.
Ledger-foot test
Tie all inputs to USD 28.70 contribution. Deep check 1 stores order alias, item-group aliases, source versions, protected pointers, full-precision transformations, display outputs, decision, reviewer, expiry, and correction route. Another reviewer must not guess cost scope, package state, fee base, units, comparison identity, or formula signs.
Find the nearest counterexample and state why it invalidates or narrows a line-by-line similar-item consolidation result. Preserve competing item, package, carrier, cost, fee, target, period, or service evidence as named scenarios instead of smoothing uncertainty into one average.
Fee-base test
Prove the percentage uses merchandise plus shipping exactly once. Deep check 2 stores order alias, item-group aliases, source versions, protected pointers, full-precision transformations, display outputs, decision, reviewer, expiry, and correction route. Another reviewer must not guess cost scope, package state, fee base, units, comparison identity, or formula signs.
Find the nearest counterexample and state why it invalidates or narrows a line-by-line similar-item consolidation result. Preserve competing item, package, carrier, cost, fee, target, period, or service evidence as named scenarios instead of smoothing uncertainty into one average.
Shipping-zero test
Show how free shipping changes funding and contribution without changing postage. Deep check 3 stores order alias, item-group aliases, source versions, protected pointers, full-precision transformations, display outputs, decision, reviewer, expiry, and correction route. Another reviewer must not guess cost scope, package state, fee base, units, comparison identity, or formula signs.
Find the nearest counterexample and state why it invalidates or narrows a line-by-line similar-item consolidation result. Preserve competing item, package, carrier, cost, fee, target, period, or service evidence as named scenarios instead of smoothing uncertainty into one average.
Weight-floor test
Prove 3.5 pounds clears the 3-pound summed-item floor. Deep check 4 stores order alias, item-group aliases, source versions, protected pointers, full-precision transformations, display outputs, decision, reviewer, expiry, and correction route. Another reviewer must not guess cost scope, package state, fee base, units, comparison identity, or formula signs.
Find the nearest counterexample and state why it invalidates or narrows a line-by-line similar-item consolidation result. Preserve competing item, package, carrier, cost, fee, target, period, or service evidence as named scenarios instead of smoothing uncertainty into one average.
Unsupported-claim test
Remove net-profit, carrier-price, delivery, and conversion language. Deep check 5 stores order alias, item-group aliases, source versions, protected pointers, full-precision transformations, display outputs, decision, reviewer, expiry, and correction route. Another reviewer must not guess cost scope, package state, fee base, units, comparison identity, or formula signs.
Find the nearest counterexample and state why it invalidates or narrows a line-by-line similar-item consolidation result. Preserve competing item, package, carrier, cost, fee, target, period, or service evidence as named scenarios instead of smoothing uncertainty into one average.
Sources and further reading
- Seller Profit Guard methodology: Comparable-order evidence, deterministic calculations, validation, correction, release, and rollback.
- Seller Profit Guard data privacy: Local-first boundaries for buyer, address, tracking, account, invoice, credential, claim, and raw order data.
- Etsy: How to Set Up Calculated Shipping: Official Etsy explanation reviewed 2026-07-31 for order weight, item dimensions, package preferences, buyer location, and calculated shipping.
- Etsy Fees & Payments Policy: Official Etsy policy reviewed 2026-07-31 for fee bases that can include shipping; sellers must enter the applicable current convention.
- UPS: Shipping Dimensions and Weight: Official U.S. UPS context reviewed 2026-07-31 for finished-package measurements, actual weight, dimensional weight, and billable-weight rules.
- FedEx: What Is Dimensional Weight?: Official U.S. FedEx context reviewed 2026-07-31 for package measurement, dimensional weight, and actual-weight comparison.
Related Seller Profit Guard tools
- Open the Combined Shipping Margin Calculator: Model two item groups sharing one parcel and one fee convention.
- Dimensional Weight Calculator: Test whether the combined parcel changes billable-weight exposure.
- Shipping Subsidy Calculator: Inspect shipping-side funding at one order grain.
- Bundle Margin Calculator: Keep product-bundle economics distinct from fulfillment consolidation.
- Packaging Cost per Order Calculator: Build a defensible package allocation.
- Contribution Margin Calculator: Carry evidenced order contribution into a broader decision.
- Methodology: Review evidence, privacy, formulas, tests, release, correction, and rollback.
- Combined Shipping Margin Formula and Inputs: Continue with a distinct combined-shipping formula, example, source, threshold, comparison, operating, interpretation, or audit task.
- Combined Shipping Margin for Mixed-Size Items: Continue with a distinct combined-shipping formula, example, source, threshold, comparison, operating, interpretation, or audit task.
- Combined Shipping Margin Calculator Mistakes: Continue with a distinct combined-shipping formula, example, source, threshold, comparison, operating, interpretation, or audit task.
- Combined Shipping Margin Data Sources: Continue with a distinct combined-shipping formula, example, source, threshold, comparison, operating, interpretation, or audit task.
- Combined Shipping Margin Decision Thresholds: Continue with a distinct combined-shipping formula, example, source, threshold, comparison, operating, interpretation, or audit task.
Next step: Open the Combined Shipping Margin Calculator.
This is operational planning help, not tax, accounting, legal, financial, or platform-policy advice. Review the Terms and disclaimer, and verify current platform rules and fee assumptions before changing prices.