Prusa Research Original Prusa MK4S 3D Printer (Fully Assembled)

Print quality and speed

TechRadar’s instrumented testing scored print quality 30/30, with dimensional accuracy averaging 0.097 mm of error (X 0.092 mm, Y 0.102 mm). In timed comparisons at 0.2 mm layers with a 0.4 mm nozzle, the MK4S finished a bowl in 3h29m against 7h05m for the Creality K1C and 4h41m for the Bambu Lab P1P, and produced 10/10 exceptional prints across a 10-print Benchy run. Surface finish was called better than both. The trade-off the same review flags is print quality affected by speed, especially at the top of the range.

Tom’s Hardware measured a volumetric flow of 24 mm³/s with Prusament PLA, 50% above the MK4’s 16 mm³/s, and produced clean 75° overhangs without supports. Its fan runs at 70% and stays quiet enough for an office. Max nozzle temperature is listed at 290 °C on Prusa’s spec sheet, though Tom’s Hardware quotes up to 300 °C.

Materials and the enclosure

Out of the box the MK4S handles PLA, PETG, Flex, PVA, PC, PP, CPE and PVB. ABS, ASA, HIPS and PA want an enclosure, which is an extra purchase and worth planning for if those materials are the point of the machine for you. Prusa also sells an MMU3 multi-material unit that runs five filaments and swaps them in 25–35 seconds, plus an accelerometer and a GPIO hackerboard. The high-flow CHT nozzle is standard and raises flow, but Prusa recommends the standard nozzle when MMU3 is in use because the high-flow nozzle increases filament waste during changes.

Repairs, parts and running costs

The MK4S is built to be worked on: Prusa says there are no welded or glued parts and everything is removable with Allen keys, and spare parts for the MK4/S family are sold through its e-shop. Prusa’s own reliability figure is a return or repair rate under 1% across roughly half a million printers, about 20 a month; that is a manufacturer claim and has not been independently audited. A 700-machine internal print farm is used as a durability testbed.

Ongoing costs are filament and print sheets. Print sheets are consumables and are not covered by warranty except for defects on delivery. An MK4 owner who wants the S improvements can buy the $99 upgrade kit instead of a new printer. Prusa’s e-shop lists the MMU3 at about $359 on its category page, though that figure was not re-verified in this pass.

Is it worth it?

Prusa’s e-shop lists the assembled MK4S at $925 and the kit at $657.40, in stock with one to three business days of preparation (Prusa, 2026-10-10). That is down from a launch retail of $1,099 and a $999 list price reported in 2024, so the figure has moved in the buyer’s favor over about two years. At or under $800 it is strong value for a reliable, repairable open-frame printer with independent test backing. The $925 direct price sits in the fair-to-good band, and it is justifiable for buyers who put print quality, offline operation, repairability and the Prusa ecosystem above maximum speed. Above $1,100, value is weak unless you specifically need Prusa’s upgrade path or already own an MK4.

Which model this is

This page covers the Original Prusa MK4S, the “S” revision of the MK4, sold as a fully assembled printer or a kit. It keeps the MK4’s Cartesian bed-slinger frame and build volume but adds a 360° cooling system, a high-flow Bondtech CHT nozzle, PC Blend Carbon Fiber printed parts, an injection-molded LCD cover, and native Wi-Fi/NFC setup. It is not the older MK4, the MK3.9/S, the Prusa CORE One or the Original Prusa XL. The US listing for the assembled printer carries ASIN B0DLKM9FZY.

Sources

Manufacturer:

• Original Prusa MK4S 3D Printer

Independent reviews:

• Original Prusa MK4S review (TechRadar)
• Prusa MK4S review (Tom’s Hardware)
• CNET 3D printer roundup