Flat rate or weight-based courier pricing: which costs less

A flat-rate courier charges the same for every parcel in a zone. A weight-based courier charges a first unit plus a step. Which one costs you less is not a matter of opinion, it is a crossover point you can calculate from your own parcel mix in about ten minutes.

This works out how to find that crossover, what each model hides, and why flat rate often looks better than it is.

The two shapes

Weight-based, which is what the QCS Lahore tariff is: PKR 180 for the first half kilo and PKR 40 for each additional half kilo inside Lahore City, plus a flat PKR 50 if the address is in the extended area. So a 1 kg parcel is PKR 220 and a 3 kg parcel is PKR 380.

Flat rate: one figure per zone, regardless of weight, usually with a weight ceiling above which it stops being flat.

Finding your crossover

1. 01Pull your last two hundred delivered parcels and their chargeable weights
2. 02Work the weight-based charge for each one and total it
3. 03Multiply the parcel count by the flat rate and total that
4. 04Compare the two totals

Do it on chargeable weight, not scale weight, or the answer is wrong. If the scale weight is 5 kg or less and dimensions were supplied, the charge is worked on the larger of the scale weight and length by width by height divided by 5000, then rounded up to the next half kilo. Chargeable weight versus actual weight works it through, and the pricing calculator will do step two for any individual parcel.

The shape of the answer

Weight-based wins when your parcels are light. Flat rate wins when they are heavy. The crossover is wherever the flat rate equals the weight-based charge for your median parcel.

With the QCS tariff as the weight-based side, against a hypothetical flat rate of PKR 350 inside Lahore City:

• 0.5 kg parcel: weight-based PKR 180, flat PKR 350. Weight-based wins by PKR 170
• 1.0 kg parcel: weight-based PKR 220, flat PKR 350. Weight-based wins by PKR 130
• 2.0 kg parcel: weight-based PKR 300, flat PKR 350. Weight-based wins by PKR 50
• 2.5 kg parcel: weight-based PKR 340, flat PKR 350. Roughly even
• 4.0 kg parcel: weight-based PKR 460, flat PKR 350. Flat wins by PKR 110

That PKR 350 is an illustration, not a competitor's price. Substitute whatever flat rate you are actually offered and the method is the same.

What flat rate hides

The weight ceiling

Almost every flat rate has one. Above it you are on a weight-based rate anyway, usually one you did not compare. Ask what the ceiling is and what happens above it before you treat the rate as flat.

The zone surcharge shape

A flat base rate with a per-unit zone surcharge is not flat. The Lahore extended area at QCS is a flat PKR 50 added once; a per-unit surcharge compounds with weight and can exceed the base on a heavy parcel. How courier pricing works covers the two shapes.

The incentive it removes

The subtle one. Under flat rate your box size stops mattering, so sellers stop caring about it. Under weight-based, shrinking a box is money, and most sellers find real savings the first time they look. If you move to flat rate and later move back, you will have acquired a habit of oversized boxes that costs you immediately.

What weight-based hides

In fairness, two things.

You cannot quote a customer a shipping figure without knowing the parcel

Flat rate lets you put one number on your site. Weight-based means either a table, a calculator, or absorbing the variance yourself. For a seller with a wide product range this is a genuine operational cost.

The first unit dominates, so splitting is punished

At half a kilo you pay PKR 360 per kilo; at 5 kg you pay PKR 108 per kilo. Two 1 kg parcels are PKR 440 and one 2 kg parcel is PKR 300. That is correct pricing, but it means a seller who ships items separately because it is easier is paying a real premium for the convenience.

Which to choose

• Light parcels, narrow weight range: weight-based, and shrink your boxes
• Heavy parcels, consistent weights: flat rate, if the ceiling is above your range
• Wide range: weight-based, and show a calculator rather than a single figure
• You want one shipping number on your site above all else: flat rate, and accept you are overpaying on the light end

The thing to check either way

Whichever model, ask whether the price is frozen at booking against a dated rate card or computed when the invoice is raised. A flat rate that can change retroactively is worse than a weight-based rate that cannot.

At QCS the rate card version is frozen into each parcel at booking and a new card never reaches backwards, and merchants are told before a change takes effect. The published tariff carries the terms, and eleven questions to ask a courier covers the rest of what to establish first.