Dimensional Weight Calculator

    Carriers bill by whichever is greater, actual weight or dimensional weight. A big light box can cost more than a small heavy one. Enter your box dimensions, actual weight, and carrier divisor to see your billable weight, whether DIM is costing you, and how much you save with smaller packaging.

    Instant calculations · Editable fee assumptions · Export-ready results

    Inputs

    Values update results instantly. Adjust fee assumptions to match your seller dashboard.

    Dimensions

    Longest side in inches.

    Second side in inches.

    Third side in inches.

    Weight

    Scale weight in pounds.

    Carrier

    Carrier's dimensional divisor.

    Only if custom selected.

    Rates

    USD

    Carrier rate for 1 lb in your zone.

    USD

    Cost per extra pound beyond first.

    Results

    Live estimates based on your inputs and editable fee assumptions.

    Cubic inches

    720

    L × W × H volume.

    Dimensional weight (raw)

    5.18

    Cubic / divisor, before round up.

    Dimensional weight (billed)

    6

    Rounded up to whole lb.

    Actual weight

    4

    Scale weight.

    Billable weight

    6

    Max of actual and DIM.

    Bills by

    DIM weight

    Actual vs DIM.

    Estimated shipping cost

    $22.50

    Based on billable weight.

    DIM surcharge vs actual

    $4.00

    Extra due to DIM.

    Surcharge %

    21.6%

    % increase from actual-only cost.

    What this means

    720 cu in / 139 = 5.18 → 6 lbs DIM. Billable 6 lbs by DIM weight. Cost $22.50 vs $18.50 actual-only, surcharge $4.00 (21.6%).

    Actual vs dimensional weight

    Interactive breakdown of fees, costs, and remaining profit.

    Distribution

    • Actual weight
      $4.00
      25.0%
    • DIM weight
      $6.00
      37.5%
    • Billable
      $6.00
      37.5%

    Total $16.00 · 3 segments · interactive

    Line-item breakdown

    Dollar amounts, share of revenue, and visual proportion.

    Cubic inches
    720
    DIM divisor
    139
    DIM weight raw
    5.18
    DIM weight billed
    6
    Actual weight
    4
    Billable weight
    6
    Cost at actual weight
    $18.50
    Cost at billable weight
    $22.50
    DIM surcharge
    $4.00
    Surcharge %
    21.6%

    Assumptions used

    • • 720 cu in / 139 = 5.18
    • • Bills by DIM weight, rounded up rule applied

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    How it works

    Methodology & formulas

    This calculator is transparent by design. Review the steps and formulas so you can trust the estimate and adjust assumptions when your dashboard differs.

    Calculation steps

    1. 1Calculate cubicInches = length × width × height.
    2. 2Resolve divisor from carrier selection or custom input.
    3. 3Dimensional raw = cubic / divisor.
    4. 4Dimensional billed = ceil(raw).
    5. 5Billable = max(actualWeight, dimensionalBilled).
    6. 6Cost = base + (billable-1)*additional.
    7. 7Surcharge = costAtBillable - costAtActual.

    Formulas

    • Cubic inches = L × W × H
    • DIM weight = cubic / divisor (round up)
    • Billable = max(actual, DIM)
    • Shipping = base + (billable-1) × perLb

    Important assumptions

    • DIM weight = (L×W×H) / divisor, rounded up to next whole pound (UPS/FedEx rule).
    • Billable weight = max(actual, DIM).
    • Shipping cost = baseRate + (billable-1)*additionalRate, min baseRate.
    • Divisor 139 for UPS and FedEx domestic daily rates, 166 for USPS Priority cubic exception.
    • Zone and service surcharges not auto-included; reflect them in base rate input.

    Worked example

    12x10x6 box at 4 lbs actual

    Box 720 cubic inches. UPS divisor 139. Actual weight 4 lbs. Base $12.50 + $2 per extra lb.

    720/139=5.18 → DIM 6 lbs. Billable 6 lbs (DIM wins over 4 actual). Cost = $12.50 + (6-1)*$2 = $22.50. Actual-only cost would be $12.50 + (4-1)*$2 = $18.50. DIM adds $4.00 (21.6% surcharge). Switching to 9x7x4 box 252/139=2 lbs billable would save $8 dropping to actual weight.

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