What these documents are for
Most carriers publish a service guide, sometimes called a rate guide, terms of service or tariff. It sets out the services offered, the price tables, the rules on size and weight, the extra charges and the conditions that apply. Alongside it, the carrier provides a zone chart or zone lookup. Together they let you work out the price of a parcel before you ship it.
The documents can be long and dense, but the pricing logic inside them is usually simple once you know the sequence. The calculation generally runs: find the zone, find the billable weight, read the rate, then add the extras.
Step 1: Find the zone
A zone is a band of distance, or a grouping of destinations, used to price delivery. The idea is that moving a parcel further generally costs more, so destinations are sorted into zones and each zone gets its own price column.
Zones are defined in different ways:
- By distance from the origin. In some domestic systems, a lower zone number means a shorter distance from the sender’s location, and a higher number means further away. The numbering and the number of zones differ between carriers, so never assume that one carrier’s Zone 4 equals another’s.
- By origin and destination pair. The zone depends on both where the parcel starts and where it ends, so the same destination can fall in different zones for senders in different places. This is why changing a warehouse location can alter prices.
- By country or region. International services often group countries into zones by region, with each group priced separately.
- By postcode. Many carriers provide a lookup in which you enter the origin and destination postal codes to get the zone.
Always use the zone chart for your own origin. A chart drawn for a different sender location will give the wrong answer.
Step 2: Work out the weight that is billed
The weight on the scale is not always the weight on the invoice. Carriers generally charge on the greater of actual weight and a volume-based figure, known as dimensional weight, which reflects the space the box takes up. A large, light box can therefore cost as much as a small, dense one. The rules for rounding also matter, since most carriers round up to the next whole unit or weight band, and the details are part of the carrier’s stated billable weight rules.
Check the divisor or formula in the service guide, as it varies between carriers and services, and note the minimum and maximum weights and dimensions allowed. Parcels over certain size limits may be reclassified, charged extra, or refused.
Step 3: Read the rate table
A rate table is usually a grid. Weight bands run down one side, zones run across the top, and each cell gives the price for that weight and zone. To use it, find the row for the billable weight and the column for the zone, and read where they meet.
Some practical notes:
- Prices usually step up at each weight break, so a parcel just over a band edge costs the rate of the next band. Trimming a little weight or size can sometimes bring a parcel into a cheaper row.
- Different services have separate tables. Make sure you are reading the table for the service level you plan to use.
- Tables may be listed for a particular effective date. Prices change over time, and the date matters.
- Contract customers may receive discounts off the published figures, or their own rate cards. The published table is then a reference point, not the price you pay.
Step 4: Add surcharges and extras
The table price is rarely the final price. The service guide lists additional charges that may apply, for example:
- Fuel adjustments, which change periodically.
- Residential or delivery area surcharges.
- Extended or remote area fees.
- Additional handling for oversize, heavy or awkwardly shaped items.
- Signature, insurance or declared value fees.
- Address correction fees.
Read the conditions for each. Some apply automatically and others only when triggered by something about the parcel. Carrier surcharges are often a meaningful share of the final bill, and fuel surcharges in particular are usually a percentage that moves over time. Add every one that applies to your typical parcels before comparing carriers.
A worked example, with made-up numbers
To see how the pieces fit, take an invented rate table. A parcel measures 40 cm by 30 cm by 20 cm and weighs 2 kg on the scale. Suppose the carrier’s volume divisor is 5,000, meaning volume in cubic centimetres divided by 5,000 gives the volumetric weight in kilograms.
Volume is 40 x 30 x 20 = 24,000 cubic centimetres. Dividing by 5,000 gives 4.8 kg. Since 4.8 kg is greater than 2 kg, the carrier would bill on 4.8 kg, typically rounded up to 5 kg. If this destination is in Zone 3 and the invented table lists 9.00 for a 5 kg parcel in that zone, the base price is 9.00. If the carrier then adds a fuel adjustment of 10 percent, that adds 0.90, for a total of 9.90, before any other surcharges.
These figures are for illustration only. Real divisors, tables and percentages differ by carrier and service.
What else to check in a service guide
Beyond price, the guide tells you things that affect how a service behaves:
- Transit times and commitments. What is promised, and under what conditions.
- Pickup and handover rules. Cut-off times, and collection charges.
- Liability limits. The standard compensation and how to claim.
- Prohibited and restricted items. Goods the carrier will not take.
- Delivery attempts. How many attempts are made and what happens afterwards.
- Time limits for claims and billing disputes. These can be short.
Keep a copy of the version you relied on, as guides change.
Using this in practice
Build a small spreadsheet that follows the four steps with your own typical parcels and destinations. It will let you compare carriers on the same basis, test how a change in box size would alter the price, and check invoices for errors. When a carrier’s invoice does not match your calculation, the zone, the billed weight and the surcharges are the first three places to look.