"How many kilos do I need?" is usually the second question a cobot buyer asks, right after "how much?" The two turn out to be tangled in a way most spec sheets hide: payload is not priced in a straight line, and in at least one case the bigger robot is the cheaper one to get into.
To test that, I did something deliberately narrow. Rather than collect prices from five vendors with five different discount structures, I took a single US distributor's live catalog — Automation Distribution — and read the whole Universal Robots lineup off it on the same day, July 2026. Same seller, same currency, same moment. Whatever else is wrong with the numbers, the comparison between them is clean.
The payload price curve
| Model | Payload | Reach | Listed price range |
|---|---|---|---|
| UR3e | 3 kg | 500 mm | $36,910.71 – $42,214.03 |
| UR5e | 5 kg | 850 mm | $39,083.16 – $43,544.43 |
| UR12e | 12.5 kg | 1,300 mm | $50,817.55 – $55,669.47 |
| UR18 | 18 kg | 950 mm | $64,506.71 – $68,434.71 |
| UR30 | 30 kg | 1,300 mm | $59,615.00 – $72,847.51 |
The ranges reflect configuration options, not haggling room, so the comparison below uses the bottom of each range consistently.
Three things fall out immediately.
Payload is cheap in bulk. Going from the UR3e to the UR30 multiplies payload by ten and price by only 1.6. Cost per kilogram of rated payload collapses from about $12,300 on the UR3e to roughly $1,990 on the UR30.
The middle of the range is where payload costs the most. The step from 3 kg to 5 kg costs about $1,086 per extra kilogram. From 5 kg to 12.5 kg it is about $1,565. From 12.5 kg to 18 kg it jumps to roughly $2,489 per kilogram — the most expensive stretch of the curve.
And then it goes negative. The UR30, at 30 kg and 1,300 mm, starts $4,891.71 below the UR18, at 18 kg and 950 mm. Twelve extra kilograms of payload and 350 mm of extra reach, for less money at the entry configuration.
Why the 18 kg model costs more than the 30 kg one
I want to be careful here, because it is easy to over-read a single catalog. Two explanations are consistent with the data, and I cannot separate them from the outside.
The first is product positioning: the UR18 is a shorter-reach, higher-speed-class arm, and reach and payload are separate cost drivers that do not have to move together. A 950 mm arm rated to 18 kg is a different engineering problem than a 1,300 mm arm rated to 30 kg, and not obviously a cheaper one.
The second is simply lifecycle and demand — newer or higher-volume models get priced differently, and the ranges overlap heavily at the top ($68,434.71 for the UR18 versus $72,847.51 for the UR30). The two models are not cleanly ranked; they overlap.
Either way, the buyer's takeaway is the same and it is practical: do not assume the next size up costs more. Price the two adjacent classes before you size down to save money.
The same effect in a finished cell
The pattern is not unique to bare arms. In Lincoln Electric's Cooper welding packages, listed by Harris Welding Supplies, stepping from the FANUC CRX-10iA/L package at $103,990.87 to the CRX-30iA package at $122,575.00 costs $18,584.13 — about 18 percent more for roughly three times the payload class. As a share of a six-figure cell, payload headroom is one of the cheaper things on the quote. Cooling, carts and aluminum capability each move the number by comparable amounts, as we detail in the Cooper price guide.
Payload is not the only axis anymore
A caution against sizing on payload alone: speed is now sold separately. When Universal Robots announced the UR15 on 12 May 2025, it claimed a 5 m/s maximum TCP speed and up to 30 percent cycle-time improvement over other UR models in pick-and-place work, at 15 kg payload. That sits between the UR12e and UR18 on payload while competing on a different axis entirely.
And if the application is genuinely light and fast, a cobot may be the wrong architecture. Epson's G6 SCARA line publishes standard cycle times of 0.33 s (450 mm), 0.36 s (550 mm) and 0.38 s (650 mm) at rated payload — numbers a collaborative arm will not touch, at a price that typically starts well below the cobots above. The trade is that a SCARA is not collaborative and generally needs guarding. Our SCARA price guide covers that range.
How I would size one
Weighing the dimensions rather than picking a winner:
- Under 5 kg, fixed task, high speed: a SCARA or delta is usually faster and cheaper. Consider a cobot only if you need the shared workspace or the frequent changeover.
- 3 to 12 kg, mixed work: this is cobot home ground, and it is also where each extra kilogram is cheapest. Buy one class above your current heaviest part; the headroom costs about $1,100 to $1,600 per kilogram here.
- 12 to 18 kg: the most expensive stretch per kilogram. Price the 30 kg class before committing — on this catalog, it was cheaper to enter.
- Above 18 kg: payload is nearly incidental to the total. Gripper mass, reach, and floor space will drive the decision more than the arm's price.
One caveat on all of it: these are one distributor's listings on one day, in a market where most vendors publish nothing at all. Ranges will differ elsewhere, and a quote for your configuration is still the only number that binds. But the shape of the curve — cheap at the bottom, expensive in the middle, flat or inverted at the top — is worth carrying into the conversation.
Sources
- Automation Distribution — Universal Robots UR5e listing (UR3e, UR12e, UR18, UR30 prices)
- Universal Robots — UR15 announcement, 12 May 2025
- Harris Welding Supplies — Lincoln Electric Cooper cobot package prices
- Epson — G6 SCARA 550 mm product page and cycle-time specification
- ABB — IRB 360 FlexPicker payload and reach variants
