Weight Slabs: Why 20 Grams Can Cost ₹38

A rate card does not have a price per kilogram. It has a price per slab: a band of weights that all cost the same. Understanding where the slab edges sit, and how the card behaves above the last one, is the difference between a seller who pays the quoted rate and one who is surprised by the invoice every week.

What a slab is

A slab is a weight range with one price. A representative Zone C surface card:

Slab	Chargeable weight	Price
1	Up to 0.5 kg	Rs 52
2	0.5 to 1 kg	Rs 78
3	1 to 2 kg	Rs 118
4	2 to 3 kg	Rs 152
5	3 to 5 kg	Rs 210
Beyond	Each additional kg over 5	Rs 36

Every parcel with a chargeable weight in a slab pays that slab’s price. A 0.51 kg parcel and a 0.99 kg parcel both pay Rs 78. A 0.49 kg parcel pays Rs 52.

The edges are cliffs

The price does not rise gradually; it steps. Going from 0.49 kg to 0.51 kg is a 50 percent increase. Going from 0.51 kg to 0.99 kg is zero. This has two consequences.

First, the weight to care about is the distance to the next edge, not the weight itself. A 0.45 kg parcel has 50 g of headroom; a 0.95 kg parcel has 50 g too, but its edge is worth Rs 40 rather than Rs 26.

Second, small packaging changes near an edge are worth a lot, and large changes in the middle of a slab are worth nothing. A parcel at 0.7 kg gains nothing from dropping to 0.6 kg. It gains Rs 26 from dropping to 0.49 kg.

How slabs differ between couriers

The structure is universal; the edges and the prices are not. Some cards have 0.5 kg steps all the way to 5 kg. Some jump from 1 kg to 2 kg to 5 kg. Some start the per-kg increment at 3 kg, others at 10 kg. The same parcel can sit in the second slab on one card and the third on another.

This is why comparing couriers per parcel matters more than comparing their headline 0.5 kg rate. A courier with a dearer 0.5 kg rate but a 1 kg first slab is cheaper for everything between 0.5 and 1 kg, which for many sellers is most of their volume.

The per-kg tail

Above the last defined slab, cards charge a fixed amount per additional kilogram, usually per whole kilogram rounded up. On the card above, a 7.3 kg parcel is Rs 210 for the first 5 kg plus 3 x Rs 36 for the next three (rounded up from 2.3), so Rs 318.

Two things to check on any card: where the tail starts, and whether the increment is per kg or per 0.5 kg. A card with a Rs 36 per kg tail and one with a Rs 20 per 0.5 kg tail look similar and are not; the second is Rs 40 per kg.

Reading your own card

On Courier Uncle the rate card page shows each courier’s slabs for each zone as the platform will bill them. To read it usefully:

1. Note where your average chargeable weight sits. If it is 0.55 kg, you are paying slab two prices for slab one parcels, and a 60 g packaging reduction moves the whole average.
2. Note the edges that fall inside your weight distribution. Those are the ones packaging can move you across.
3. For each courier, note the slab your typical parcel falls in. The cheapest courier for your typical parcel is often not the one with the cheapest first slab.

Slabs and discrepancies

A weight discrepancy charge is a slab difference. Declared 0.48 kg, hub measured 0.55 kg: slab one to slab two, Rs 26. Declared 0.6 kg, hub measured 0.9 kg: same slab, no charge. The hub’s reading only costs money when it crosses an edge, which is why accurate declarations near an edge matter most.

Designing around the edges

Sellers who know their card design packaging to sit just under an edge. If the product is 430 g, the packaging budget is 70 g, and a 15 g mailer is the answer. If the product is 520 g, it is in slab two regardless, and the packaging can be whatever protects it best, up to 480 g more. Knowing the edge tells you whether to fight for grams or not bother.

Frequently asked questions

Is a 0.5 kg parcel in the first slab or the second?

Cards define slabs as “up to and including” the edge, so 0.500 kg is in the first slab and 0.501 kg is in the second. Check the card’s wording; Courier Uncle’s calculator applies each courier’s own rule.

Do slabs apply to dead weight or chargeable weight?

Chargeable weight, which is the higher of dead and volumetric. A light parcel in a big box lands in the slab its volumetric weight puts it in.

Why does one courier have more slabs than another?

Card design. More slabs means finer steps and less headroom lost; fewer slabs means bigger jumps. Neither is cheaper in general; it depends on where your parcels fall.

Is the per-kg tail rounded up?

On most cards, to the next whole kilogram. A 5.1 kg parcel pays for 6 kg on a per-kg card. Some cards round to the next 0.5 kg. The card says which.

Are slabs the same across zones?

The edges are the same; the prices differ by zone. A 0.5 to 1 kg parcel is slab two in every zone, but slab two costs more in Zone D than in Zone A.

Can I see the slab a shipment was billed on?

Yes. The shipment record on Courier Uncle carries the chargeable weight and the zone it was billed on, and the invoice line shows the resulting rate.

Ship smarter with Courier Uncle

Every courier’s slabs, every zone, on one page, applied to your actual parcel. Compare your typical parcel across all twelve couriers.