THE NUMBERS, EXPLAINED
How to use this calculator.
Use dimensions already rounded under your carrier rules and your quoted divisor. Take the larger of actual and dimensional weight, then round up to the supplied billing increment. This is not a live shipping quote.
Start with your inputs
Enter length after carrier rounding (cm), width after carrier rounding (cm), height after carrier rounding (cm), carrier divisor (cm³/kg), actual weight (kg), billing increment (kg). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Length after carrier rounding (cm) | 40 |
| Width after carrier rounding (cm) | 30 |
| Height after carrier rounding (cm) | 20 |
| Carrier divisor (cm³/kg) | 5000 |
| Actual weight (kg) | 3 |
| Billing increment (kg) | 0.5 |
A worked example
With the example inputs above, dimensional weight (kg) is 4.8. Change the inputs to explore your own scenario.
Putting the example numbers into the formula
Dimensional weight (kg)
(40) × (30) × (20) ÷ (5000) = 4.8
Dimensional excess over actual (kg)
max(0,(40) × (30) × (20) ÷ (5000)-(3)) = 1.8
| Result | Example answer |
|---|---|
| Dimensional weight (kg) | 4.8 |
| Chargeable weight (kg) | 5 |
| Dimensional excess over actual (kg) | 1.8 |
How this is calculated
Dimensional weight (kg)
a × b × c ÷ d
Chargeable weight (kg)
roundUp(max(a × b × c ÷ d,e) ÷ f) × f
Dimensional excess over actual (kg)
max(0,a × b × c ÷ d-e)
Symbols and units
- a
- Length after carrier rounding (cm)
- b
- Width after carrier rounding (cm)
- c
- Height after carrier rounding (cm)
- d
- Carrier divisor (cm³/kg)
- e
- Actual weight (kg)
- f
- Billing increment (kg)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Calculation steps and notation
max(x, y, …) selects the largest value.
roundUp(x) rounds up to the next whole number. Values within two floating-point rounding units of an integer are treated as that integer.
Assumptions and limits
Use dimensions already rounded under your carrier rules and your quoted divisor. Take the larger of actual and dimensional weight, then round up to the supplied billing increment. This is not a live shipping quote.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Dimensional weight (kg); Chargeable weight (kg); Dimensional excess over actual (kg). The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Use dimensions already rounded under your carrier rules and your quoted divisor. Take the larger of actual and dimensional weight, then round up to the supplied billing increment. This is not a live shipping quote.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Further reading
FedEx: dimensional weight method ↗
Background reading; this does not imply endorsement or independent review of SumFizz.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
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