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Three calculators for the questions a finds list raises

Three questions, three calculators

Each one answers a question that a finds list raises and does not resolve. All three run in the browser, and nothing typed into them is transmitted.

4Service shapes modelled
Economy air, standard air, priority air and sea-rail — shapes rather than rates, because rates move
5000Default volumetric divisor
Switchable to 6000, 8000 or 12000, since carriers differ
19Size rows in the converter
Centimetres against EU, UK and US labels for footwear
0Values stored or sent
Everything is computed locally and discarded when the tab closes

A calculator that rounds away the awkward cases is worse than no calculator, so each tool names its assumptions on its own page rather than in a footnote.

Start with the volumetric figure

The most common surprise on a first parcel is a light, bulky box billed on its dimensions. Thirty seconds here prevents it.

Volumetric—
Actual—
Billable—

—

!
The divisor depends on the line. 6,000 is common for air, but sea and rail lines often use 8,000 or 12,000 — always read the divisor on the line you are quoting. Open the weight calculator on the index

Which tool to open, in order

The order matters, because each answer changes the next question.

  1. Volumetric weight first

    If a parcel is bulky, this decides whether the billed figure is the scale or the calculation. Until that is settled, any cost estimate is guesswork.

  2. Then the cost estimator

    With a billing weight in hand, the estimator shows how the four service shapes diverge and which one is cheapest for this particular parcel.

  3. Then the size converter, if it is footwear

    Sizing is the other half of the mistake surface. A measurement in centimetres is portable between factories; a label is not.

  4. Keep the numbers, not the page

    Write the three figures down. The band between the cheapest and dearest route on one parcel is often larger than any coupon will ever be.

The three tools compared

What each one needs from you, what it gives back, and where its answer stops being reliable.

Calculators on this site
ToolInputsOutputWhere it stops
Shipping cost estimatorWeight, item count, domestic leg, service fee, exchange rateFour route costs, a cheapest-route summary and a per-kilogram all-in figurePublished fee shapes, not live rates — the agent’s order screen is the authority
Volumetric weightLength, width, height, actual weight, divisorVolumetric weight, the billed weight and which of the two appliesCarrier-specific divisors vary; four common values are offered
Size converterFoot length in centimetresNearest EU, UK and US labels, with a warning when between rowsFootwear only, and only as good as the measurement you take
The fourth column is the point. A tool that does not state its own limit is an advertisement for itself.

Tool questions

Four answers about how these calculators behave.

Do these tools send my numbers anywhere?
No. All three are client-side JavaScript. Nothing typed into a field is submitted, stored or logged, and the pages keep working after the first load.
Why does the estimator use fee shapes rather than rates?
Because rates change without notice and a published rate is stale almost immediately. Four named service shapes — economy air, standard air, priority air and sea-rail — stay useful because their relative behaviour is stable even as their prices move.
How accurate is the shipping estimate?
It is a comparison tool, not a quotation. Its value is showing how widely routes diverge on one parcel and where the per-kilogram figure settles. The binding number is always the one on the agent’s order screen.
Which divisor should I use for volumetric weight?
Whichever your carrier applies, which is why four common values are selectable. If you do not know, run it at 5000 and 6000: the difference tells you how much the divisor matters on your parcel.

The estimator is the one people come back to

Four service shapes, a cheapest-route summary and a per-kilogram figure. It answers the question the recorded price on a listing does not.