Why Accurate Shipping Costs Matter

Let’s break down three main methods.

Manual Formula to Calculate Shipping Cost

To manually calculate shipping, you’ll typically factor in:

  • Package weight and dimensions
  • Shipping distance
  • Carrier base rate + any surcharges

Formula:

Shipping Cost = (Weight × Rate per kg) + Handling Fees + Carrier Surcharges

Assume you ship a 2kg package via a carrier that charges $5 per kg, with a $3 handling fee.
In Excel: =2*5 + 3

 Result: $13 total shipping cost

This method is useful for small stores or when comparing carriers manually.

Dimensional Weight Formula Explained

Carriers like FedEx, UPS, and DHL use dimensional weight (DIM weight) to price bulky but light packages.

Formula:

DIM Weight (lbs) = (Length × Width × Height) ÷ DIM Divisor

Most carriers use a divisor of 139 (for inches).
So, a 20x15x10 inch box:
= (20×15×10) ÷ 139 = ~22 lbs (billed weight)

If the DIM weight is higher than the actual weight, you’re charged for the higher number. This catches many sellers off guard.

Flat Rate vs. Real-Time Carrier Rates

Shipping Cost Comparison (Domestic vs. International)

Understanding your true shipping costs is critical to your store’s success. But calculating and tracking them manually? That’s time-consuming and prone to errors. With TrueProfit, you can instantly access all your essential metrics in one place - no spreadsheets, no stress. Join thousands of Shopify merchants who have unlocked a clearer view of their net profit with our real-time profit tracking solution.

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Leah Tran

Content Executive at TrueProfit & eCommerce Content Specialist

Leah Tran

Leah Tran is a Content Specialist at TrueProfit, where she crafts SEO-driven and data-backed content to help eCommerce merchants understand their true profitability. With a strong background in content writing, research, and editorial content, she focuses on making complex financial and business concepts clear, engaging, and actionable for Shopify merchants.

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