Volumetric · Dimensional · Chargeable
Carriers bill the bigger number.
Enter a box and its weight. Find out which number you're actually paying for.
Consignment
Length × width × height, in centimetres
Kilograms
Billing readout
—Enter a box to see how it will be billed.
The part other calculators skip
—
- Rounding appliedEach carrier's own rule — up, nearest, or none. Most calculators use one rule for all.
- Reverse thresholdThe largest box that still bills on actual weight, not just what you're paying now.
- Sourced & datedEvery divisor links to the carrier's own page with the date it was checked.
Two carriers people expect to find here
Royal Mail
Doesn't use volumetric weight for UK domestic post at all. Pricing runs on fixed format categories — Letter, Large Letter, Small Parcel, Medium Parcel — and actual weight. A big light box costs the same as a dense one in the same format band. International items routed by air can be subject to airline volumetric rules, which is a different calculation from the courier divisors above.
Evri
Prices UK domestic parcels on weight and size band rather than a published volumetric divisor. Evri does apply volumetric weight to some international destinations, but doesn't publish the divisor in the same place the couriers above do — so rather than guess, it's left out. If you need an Evri figure, get it from your account quote.
Every divisor above is taken from the carrier's own published guidance, with the date it was last checked shown next to it. Negotiated contract rates can differ from published divisors — your invoice is the final word.
Sources
Full reference table with rounding rules and the figures we chose not to publish: carrier divisor cheat sheet. Peak season demand surcharges: surcharge tracker.