Calculator Inputs
Example Data Table
Use this example to verify your setup before entering real orders.
| Item | Qty | Unit Price | Unit Weight | Dims (L×W×H) |
|---|---|---|---|---|
| T-Shirt | 3 | 12.99 | 0.25 | — |
| Mug | 2 | 9.50 | 0.45 | 12×12×10 |
| Notebook | 5 | 4.25 | 0.20 | 21×15×2 |
Formula Used
- Total allocatable shipping = shipping + insurance + handling + surcharges − discounts
- Dimensional weight per unit = (L × W × H) ÷ dimensional factor
- Billable weight per unit = max(actual unit weight, dimensional weight)
- Line basis depends on method:
- Weight: billable weight per unit × quantity
- Value: unit price × quantity
- Quantity: quantity
- Hybrid: (weight share × normalized weight) + (value share × normalized value)
- Allocated shipping per line = total allocatable shipping × (line basis ÷ sum of bases)
- Landed unit cost = unit price + shipping per unit + duty per unit + tax per unit
How to Use This Calculator
- Enter shipment-level costs (freight, insurance, handling, surcharges, discounts).
- Select an allocation method that matches your accounting policy.
- Add all items in the shipment with quantity and unit price.
- Optional: add weight and dimensions to use billable weight.
- Optional: add duty and tax rates to estimate landed costs.
- Click Allocate Shipping Costs, then download CSV or PDF.
Cost allocation improves SKU margin accuracy
When freight is recorded only at the order level, SKU profitability is understated for heavy or bulky items and overstated for light add-ons. A consistent allocation rule converts shipment cost into per-line cost. For example, a PKR 5,000 shipment spread across 10 lines can shift gross margin by 2–8 percentage points, depending on mix and weight.
Choosing the right allocation basis
Weight allocation reflects carrier billing when charges scale with kilograms or volumetric weight. Value allocation supports insured or high-value goods where risk dominates. Quantity allocation is practical for flat-rate packaging. Hybrid models are common in marketplaces: a 60% weight and 40% value blend often tracks both carrier cost and service expectations for premium items.
Dimensional weight reduces surprises
Carriers frequently bill by the larger of actual and dimensional weight. Using the formula (L×W×H) ÷ factor, the calculator computes billable weight per unit and multiplies by quantity. A 12×12×10 cm mug with factor 5000 yields 0.288 kg volumetric weight; if the actual weight is 0.45 kg, the billable value remains 0.45 kg.
Rounding control supports clean reconciliation
Finance teams need allocations that reconcile to the invoice. This tool supports standard rounding, always-up, and always-down modes with 0–4 decimals. If rounding creates a small difference, the largest line is adjusted so that allocated shipping equals the allocatable total exactly, which simplifies month-end close and audit sampling.
Landed cost adds duty and tax visibility
For cross-border fulfillment, landed cost is the price your customer experience actually carries. Duty is estimated as line value × duty rate, and tax can be calculated on value + duty, optionally including allocated shipping. This makes it easier to set free-shipping thresholds, compare DDP vs DAP policies, and quantify margin impact per destination.
Operational use cases in ecommerce workflows
Use allocated shipping for partial refunds, bundle pricing, and channel-level contribution reporting. In returns, per-item shipping is essential for fair restocking fees. In procurement, landed unit cost supports reorder decisions when carrier rates rise. Pair allocations with your SKU catalog to spot products that are “shipping heavy” and require packaging redesign.
FAQs
Which allocation method should I use for flat-rate shipping?
Use Quantity if every item consumes similar packaging effort. If some items are oversized, use Weight or Hybrid to reflect carrier billing and avoid undercharging bulky products.
Why does the calculator adjust one line after rounding?
Rounding each line independently can create a small difference from the shipping total. The calculator applies the difference to the largest line so allocated shipping matches the shipment total exactly.
What is dimensional factor and why does it matter?
Dimensional factor converts volume into a “volumetric weight.” Carriers bill the higher of actual and volumetric weight. Enter your carrier’s factor to model billable weight more accurately.
Can I estimate landed cost for international orders?
Yes. Enter duty and tax rates to estimate duty and tax per line. Optionally include allocated shipping in the tax base to match jurisdictions that tax delivered cost.
Will CSV and PDF include my full allocation details?
CSV exports item-level pricing, billable weight, allocated shipping, duty, tax, and landed costs. PDF exports the on-screen results table for sharing with finance or operations teams.
How should I use hybrid weight and value shares?
Set shares to mirror your cost drivers. Start with 70/30 (weight/value) for carrier-driven costs, or 50/50 if premium items require more service. Validate against recent invoices.