Almost always because they aren't quoting the same job. Two carriers reading the same request will make different assumptions about equipment, access, service level and liability, and each of those assumptions has a price. The gap you're looking at is usually the difference between what they assumed, not the difference between what they charge.
You sent an identical email to three carriers. The quotes came back at figures so far apart that one of them must be wrong. This is normal, it happens on most lanes, and it's rarely because one carrier is gouging you.
Freight pricing isn't a lookup. It's a set of judgements about a job that was described in a paragraph, and different people judge differently.
Any freight request leaves something unstated. Carriers don't leave those blanks empty — they fill them, using whatever their experience of similar shipments suggests.
One carrier reads “deliver to 14 Mill Road” and assumes a commercial address with a forklift. Another looks at the same line, recognises the street type, and prices a liftgate and a residential surcharge. Neither is being dishonest. One of them is going to be right, and if it's the second one, the first quote was never real.
This is why the cheapest quote correlates so poorly with the cheapest shipment. The lowest number is frequently the carrier who assumed the most favourable version of your job.
Standard freight, expedited, and guaranteed-window are three products with three prices. If your request didn't specify, you may have received one of each.
The same applies to how the freight moves. A shipment consolidated with other people's goods and moving through a depot network costs less and takes longer than a dedicated vehicle going direct. Both are legitimate answers to “move this pallet”.
Equipment choice moves prices more than most shippers expect. A tail-lift vehicle, a vehicle that needs a forklift at both ends, and a smaller rigid truck that can access a narrow street are different cost bases.
On international moves the equivalent question is which routing, which service, and — where a sea leg is involved — how the freight is consolidated. A quote built around a slower service and one built around a faster one aren't comparable numbers even though they describe the same origin and destination.
Freight is priced on both weight and the space it occupies, and carriers convert between the two using their own formulas. A light, bulky shipment can be charged on its volume rather than its actual weight, and the conversion factor isn't universal.
The practical consequence: two carriers can take the identical dimensions you supplied and arrive at two different chargeable weights, entirely legitimately, before either of them has quoted a rate.
Fuel surcharge as a line item or baked into the rate. Waiting time allowance of thirty minutes or ninety. Liability capped at one figure or another. Customs handling included on a cross-border move, or quietly excluded.
Each of those is worth real money, and none of them show up if you only read the total. A quote is a scope document that happens to end in a number.
Sometimes the gap is real and in your favour. Carriers have networks, and a lane that fits an existing route is cheaper for them to serve than one that doesn't.
If a carrier already runs a vehicle back along your route empty, filling it is close to free revenue. A carrier who'd have to send a truck specially has an entirely different cost. Same shipment, same day, genuinely different economics. This is the case where the cheap quote is exactly what it appears to be — and it's why quoting more than one carrier is worth doing at all.
You normalise before you compare. Write down what the job actually is — equipment at each end, service level, what's included — and then go back to each carrier and confirm they quoted that. The gap that survives is a real price difference. The gap that disappears was never a price difference.
The part that stings is that this is unavoidable work, it has to happen on every shipment, and it takes longer than getting the quotes did.
It's also, specifically, the work this platform exists to remove. Replies come back in whatever format each carrier chose — a PDF, a paragraph, a table pasted into an email — and they get read, normalised, and lined up so the numbers describe the same job. A person reviews what's left and picks the option before it reaches you. There's more on that sequence on the how it works page, or you can walk through it in the demo.
If you're doing it yourself, do it anyway. The half hour of normalising is cheaper than the revised invoice.