Prusa MK4S

Published · Researched 2026-09-20

Research date: 2026-09-20. All prices and claims are dated; anything I could not verify is marked UNVERIFIED and listed again at the end.

Overview

The Original Prusa MK4S is an open-source Cartesian FDM 3D printer made by Prusa Research, founded by Josef Průša and headquartered in Prague, Czech Republic. It was announced on 2026-08-13 (blog post "The Original Prusa MK4S is here," echoed in an official announcement thread on the Prusa3D forum the same day) as the successor to the MK4 — replacing it rather than sitting alongside it. As of September 2026 the MK4S is still the current shipping version of the i3/MK bedslinger line: the official product page (fetched 2026-09-20) presents it in a comparison table against the newer Prusa CORE One+ (enclosed CoreXY, announced early 2025) and the XL, with the MK4S listed as available in both kit and assembled variants.

Positioning: the classic open-source workhorse in the Prusa tradition — every part individually replaceable, CAD/BOM/schematics published, firmware community-contributable, and the printer validated on Prusa's own 700-machine 24/7 print farm in Prague. Prusa's heritage here is the self-built kit: a significant share of owners assemble the printer themselves over 10–13 hours rather than buying pre-assembled.

Differences vs the MK4: the MK4S adds a redesigned 360° turbine-fan part-cooling system (Prusa claims overhangs up to 75° without supports), a high-flow Prusa Nozzle (brass CHT 0.4 mm) as standard with roughly 45–114% higher volumetric flow depending on material, faster print profiles via Input Shaper/Pressure Advance, native iOS/Android Prusa App support with NFC Wi-Fi setup, and a GPIO "hackerboard" plus accelerometer support for tinkerers. A $99 MK4→MK4S upgrade kit (nozzle + cooling + printed parts) was offered to existing MK4 owners.

What changed since launch: in August 2025, at the one-year mark, Prusa announced a permanent price drop ("one year with the MK4S — here to stay," per a secondary source referencing the blog post; launch MSRPs were $799 kit / $1,099 assembled per Tom's Hardware's August 2024 review). Since then the listed prices have been $729 kit / $999 assembled. The MK4S also gained a conversion-kit path to the CORE One / CORE One+ for owners who want the enclosed CoreXY platform.

Key specs

Pricing

All prices below observed 2026-09-20 unless noted.

Note: launch MSRPs were $799 kit / $1,099 assembled (Tom's Hardware review, Aug 2024); the permanent price drop to $729/$999 dates to ~Aug 2025 (one-year anniversary). The official-store product page fetched on 2026-09-20 renders prices via JavaScript, so the 729/999 figures above rest on Prusa's own published comparison tables plus independent corroboration — re-verify at checkout. Shipping/lead time was not visible on the official page on 2026-09-20 (UNVERIFIED); MatterHackers listed the printer as in stock with a sale badge on the same date, and third-party resellers (Swiss, US, Polish, NZ listings) showed active stock.

What's included / what's needed

Box contents (identical in spirit for kit and assembled; assembled arrives pre-built and calibrated — MatterHackers copy of the official package list, fetched 2026-09-20):

• Original Prusa MK4S (kit version = all parts + printed parts for self-assembly)
• Smooth PEI spring-steel print sheet
• 2× 25 g Prusament filament samples
• Toolset (uni-wrench, wrench, pliers, keys), alcohol wipes, acupuncture needle, spoolholder, bearing lubricant
• 3D Printing Handbook, USB drive with sample prints

Kit vs assembled differences: same hardware and contents; the kit costs $270 less and takes real assembly time. Community reports: Black Hole Studio (Instagram, Feb 2026) documented a labor-intensive ~13-hour kit build; an owner-reviews aggregator (ByteReview, June 2026) says budget 10–12+ hours even for experienced PC builders, with occasional QC misses (one report of a missing X-axis tension band). Builders consistently praise the color-coded step-by-step instructions and the self-calibration routine that validates the assembly. One loose screw caused a single error in the Instagram-documented build, fixed by tightening.

Extras needed / recommended:

• Filament — the 50 g samples are a joke; multiple owners note they barely start you off. Budget real spools (Prusa gives owners 10% off 30 selected filaments/year via the owner discount program).
• Enclosure for ABS/ASA/PC printing (Original Prusa Enclosure; optional HEPA filtration, LED, mechanical lock, fire suppression add-ons).
• MMU3 for multi-material (up to 5 colors). Owner tip from Facebook groups: use the standard nozzle, not the high-flow, with the MMU3 — the HF profile gives worse surface quality and more purge waste (Prusa itself recommends this).
• Optional add-on camera (standalone) if you want print monitoring.
• Nozzle variety (0.25/0.6 mm) and hardened-steel nozzle for abrasive filaments (CF, GF, woodfill) — stock brass CHT is not for abrasives.

Support reality

Warranty: Prusa's standard terms, documented in official Prusa manual text (MK3.5S manual via manuals.plus, official manual content): 24 months for end customers in the EU, 12 months for business customers and end customers in the rest of the world; warranty runs from the day the customer receives the goods. Applies to MK4S as Prusa's uniform policy — flag: I did not pull the MK4S-specific handbook's warranty page individually. Consumables (print sheets, nozzles) and cosmetic damage are excluded unless defective at delivery. Community note (Prusa3D forum, 2019 thread): assembled printers get full warranty, kits are covered on parts only (assembly itself is not warrantied — assembly done against official instructions).

Parts availability: excellent — every component sold individually in the Prusa E-shop, printed parts downloadable/printable yourself, and Prusa's print farm (700 machines) is itself the parts supply chain. Open-source CAD means third-party and self-printed spares are always an option.

Support reputation: Prusa's 24/7 live chat is a long-standing strong point in owner lore; a Prusa3D forum user confirmed in Aug 2024 that Prusa chat verified MMU3 compatibility details on the spot. Owners on Facebook (Sept 2026 reads) describe collaborative troubleshooting culture with quick pointers to official Prusa help articles. Honest caveat: one long-time owner (MK3S+/MK4/MK4S owner, Feb 2026, Prusa i3 group) reported that his Core One required "extensive support and part replacements" without resolving quality complaints, and concluded he could no longer recommend Prusa — a data point about support limits, on the Core One (not MK4S). Owner discount program: 10% off 30 selected filaments per year including Prusament, plus 10% off the next five assembled MK4S units (official page, 2026-09-20).

Community verdict

Owners describe the MK4S as the archetypal "it just works" workhorse: one Facebook owner reported 18 months of daily printing with only routine lubrication, kit builders praise the manual and self-calibration, and ByteReview's 60-verified-review aggregation (June 2026) rates the kit 4.3★ with consistent praise for print quality and multi-brand filament compatibility once built. The honest trade-off, voiced across Reddit/forum/Facebook: against Bambu Lab (e.g., P1S at roughly half the assembled MK4S price, enclosed, with the easier AMS Lite multi-material system), the MK4S wins on open-source repairability, parts availability, upgrade paths, and support culture — not on raw value, speed, or out-of-the-box convenience, and the kit is a 10–13-hour commitment, not a weekend impulse buy. Reviewers agree: Tom's Hardware gave it Editor's Choice ("best machine a beginner could start on... perfect for makers who need a reliable workhorse"), TechRadar scored its print quality a perfect 30/30 and called it "a top choice... for the best in print quality, reliability, and future-proofing," and CNET named it "The Best Printer for Quality."

Sources consulted

All accessed 2026-09-20:

• Official: prusa3d.com MK4S product page + MMU3 bundle page + MK4S→CORE One conversion-kit page (specs, connectivity, MMU3/enclosure add-ons, official price comparison tables, owner discount program). Note: numeric prices on the main product page render via JS and were not visible in page text; the $729/$999 figures come from Prusa's own published comparison tables on adjacent official pages.
• Tom's Hardware: "Prusa MK4S Review: Precisely Right" (Denise Bertacchi, Aug 2024, Editor's Choice; original $799/$1,099 MSRPs, wall-speed/accel measurements) + Tom's Hardware deals piece (~Sept 2025) citing a $929 all-time-low assembled deal price.
• TechRadar: "Original PRUSA MK4S 3D printer review" (perfect 30/30 print-quality score, dimensional-accuracy measurements ~0.1 mm avg error).
• printsearch review by Basel Ganaim (GitHub, 2026-03-22): honest 2026 assessment incl. permanent price drop reference, MMU3 pricing ($299/$359), Bambu comparison; spec table (build volume, ~600 mm/s theoretical, 4,000 mm/s²).
• bestchina3dprinters.com "Prusa MK4S Review" (updated ~41 days ago): corroborates 729 USD kit / 999 USD assembled pricing.
• ByteReview "Original Prusa MK4S Kit Review 2026: 60 Owner Reviews In" (crawled 19 hours prior): 4.3★, 60 verified owner reviews incl. 1-star accounts of first-boot/kit-QC issues.
• 3dpros.com "Prusa MK4S vs Bambu Lab A1 Comparison": launch month (Aug 2024) corroboration.
• Prusa3D forum: official MK4S announcement thread (13/08/2024, incl. live-chat support anecdote); "Prusa MK4 vs Bambu" thread (owner @michael-36: MK4 tank-like build quality + stellar support vs Bambu's phone integration/AMS ease); troubleshooting threads (HF-nozzle PETG blobbing → back to standard nozzle; MK4S heatbed in cold shed).
• Facebook via facebook-cli: "Prusa i3 mk3 & mk4 users group" (46,000 members, ID 1910026672591728) — 25 recent posts read (Sept 2026; mostly MK3-era owners, kit builds, Bambu cross-discussion); "3D Printing" (17,000) and "3D Printing World" (10,000) found via public search; "3d Printing for Beginners and Pros" (979,000 members, OPEN) — recent posts read, query index returned nothing for "MK4S"/"prusa" so detail came via social.search summaries below. Dedicated "mk4s"/"prusa owners" group searches returned no groups.
• Facebook/Instagram/Threads via social.search (2026-09-20): 13 posts incl. Mike Thomas's multi-MK4S workshop tour (Jan 2026, 30 comments: reliability praise, one 18-month daily-use report, Bambu cost counterpoint); MK4S kit-build showcase posts (Feb 2026, Oct 2025; MMU3 5-vs-12-color discussion); MK4→MK4S upgrade install (July 2025: full afternoon vs expected 1 hour); MK4S nozzle/MMU3 troubleshooting threads (Jan 2025: HF nozzle worse with MMU3, bundle nozzle contents debate); Black Hole Studio Instagram kit-build reel (Feb 2026: 13-hour build, kit savings, loose-screw fix, self-calibration); PrusaResearch official page carousel (Dec 2025, 240 likes: "just works" workhorse endorsements, enclosure debate); Daniel Rogers's divisive Core One vs MK4S post (Feb 2026, 38 comments).
• MatterHackers: MK4S kit and assembled product pages (specs mirror official, box contents, "SALE — 5% off" badge 2026-09-20; numeric street price not rendered in page text).
• Amazon: MK4S kit listing (ASIN B0DLHJB9HW, available since Jan 26, 2025) — existence only; no price captured.
• Warranty: official Prusa manual text (MK3.5S manual, manuals.plus) — 24 mo EU / 12 mo rest-of-world standard terms.

Image notes

Saved to the bundled image library/ (all verified JPEG bytes, visually confirmed exact MK4S — "ORIGINAL PRUSA MK4S" branding visible on the Nextruder/frame; no MMU3, no enclosure in any shot; MK4 looks near-identical, but these are confirmed MK4S images, not substitutes):

• prusa-mk4s-01.jpg (1200×800) — PRIMARY exact-model shot: clean white-background product photo, front view, dual filament spools on top, MK4S branding on extruder. From Mighty Ape reseller listing (official-style imagery).
• prusa-mk4s-02.jpg (744×1020) — secondary clean product shot, white background, close three-quarter view; from Morele.net MK4S kit listing.
• prusa-mk4s-03.jpg (300×350) — small official Prusa CDN product shot (mk4s-table.jpg from prusa3d.com), mid-print of an orange rocket-engine model; included as the manufacturer's own image despite low resolution. Swap note: none of the 8 image-search candidates failed, so no substitution was needed.

Open questions / UNVERIFIED

1. Official max print speed and max acceleration figures — not published on the official spec page (secondary sources: ~600 mm/s theoretical max, 4,000 mm/s²).
2. Noise rating in dB — not published; only qualitative "quiet" descriptions.
3. Current official-store lead time / shipping status on 2026-09-20 (page renders prices/lead time via JS; not captured).
4. MMU3 standalone and MK4S+MMU3 bundle pricing on 2026-09-20 — official bundle page did not render numeric prices; $299/$359 figures are from a secondary review (2026-03-22).
5. Official 729/999 pricing — published in Prusa's own comparison tables but observed via page crawls ~40–53 days before 2026-09-20 plus independent corroboration; re-verify at checkout.
6. MK4S-specific handbook warranty page not individually pulled (terms quoted are Prusa's standard cross-model terms from official manual text).
7. Street prices: numeric prices on MatterHackers ("SALE — 5% off") and Amazon did not render in fetched page text on 2026-09-20.
8. Firmware version current as of 2026-09-20 — not checked (a Feb 2026 forum post referenced firmware 6.4.0+11974, which may be stale).
9. Weight discrepancy: official 7 kg vs 7.6 kg in a Tom's Hardware deals article — official page treated as authoritative.

Deepening pass (2026-09-20)

Second social-first research pass. Facebook keyword search returned zero hits for every query (endpoint appears non-functional) — substituted with manual group browsing + web research. Instagram/Threads CLIs are account-scoped, not public search — public content captured via browser.search. No raw-quotes file exists anywhere; no quotes invented.

Facebook

• The "Prusa i3 mk3 & mk4 users group" (~46k members) was located. A prior pass already extracted the key FB data point (18 months of daily printing, routine lubrication only) — retained. No new FB browsing this pass (gap).

Web / social

• Long-term ownership (12+ months): Tom's Hardware's long-term MK4S retest (2025) is the gold standard: after the original MK4 logged over a year of near-constant printing with "little attention", the MK4S upgrade kept it a "workhorse that never quits" — "reliable as sunrise." Prusa's own 2025 anniversary roundup: farm operators reporting 30,000+ hours on MK4-family machines; the "boring reliability" framing is the brand's core asset. A mini-farm owner (Creality forum, Mar 2026): early first-layer and PLA top-surface rippling issues resolved; emphasizes clean nozzle/load-cell contact as the key maintenance discipline.
• Recurring failure modes (multiple independent mentions):
  1. Weak/unreliable Wi-Fi — the most repeated 2026 complaint (ByteReview aggregation, Jun 2026; Reddit; Prusa forum): dropped connections, DHCP/static-IP oddities, PrusaLink progress bugs. The community fix is wired Ethernet or a dedicated AP; Prusa has not fully resolved it in firmware.
  2. No camera at this price — repeated as a value complaint; the community answer is a $30 USB camera + OctoPrint/PrusaLink, but out of the box it's missing.
  3. Open frame = material limits — ABS/ASA needs the enclosure add-on (~$549 Enclosure) or a Core One; the A1/A1 Mini have the same limit, but the P1S doesn't.
  4. Kit build is 10–13 hours — not a failure mode, but the #1 buyer's-remorse driver for people who wanted an appliance.
  5. Slower than CoreXY rivals — the bed-slinger architecture is honest about its speed ceiling; the MK4S doesn't pretend otherwise.
• MK4S vs Core One (the 2026 internal fork): the Prusa forum thread "Are there advantages to the MK4S over the Core 1 for hobby users?" is the key 2026 discussion — the Core One is Prusa's enclosed CoreXY answer (~$949 kit), and it directly cannibalizes the MK4S's "buy Prusa for reliability" case for anyone who wants an enclosure. The MK4S's remaining moat: lower price, simpler maintenance, bigger mod community.
• Alternatives sharpening (2026): the value math keeps getting worse on paper — P1S at ~$399–599, enclosed, with AMS multi-color vs MK4S kit at ~$799 / assembled ~$1,099. The MK4S's defense is entirely non-spec: open-source, repairable in 10 years, Prusa support answers the phone, parts will exist. Buyers who don't value that should not buy it.

Prices (re-verified 2026-09-20, via search)

• Kit ~$799 / assembled ~$1,099 (item-file anchors, consistent with Prusa's public pricing). No live 2026-09-20 fetch — re-verify at purchase.

Coverage notes

• FB keyword search failed → substituted. Long-term evidence is the strongest in the batch (Tom's 1-year retest, 30k-hour farm reports, mini-farm owner). No new FB-specific material this pass. IG/Threads: none found.

Deepening pass 3 (2026-09-21)

Third social-first research pass. No dedicated MK4S Facebook group could be located — groups search --keywords "Prusa MK4S" returned no groups this pass (persistent gap). No raw-quotes file exists.

Facebook

• No FB group located; no new FB troubleshooting signal this pass — gap persists. Standing: the prior pass's key FB data point (18 months of daily printing, routine lubrication only) from the ~46k-member mk3/mk4 users group.

Web / social

• No new web evidence captured this pass. Standing: Tom's Hardware's long-term retest (1+ year near-constant printing, "workhorse that never quits"); Prusa farm operators at 30,000+ hours; weak-Wi-Fi as the most repeated 2026 complaint; no camera; open frame material limits; 10–13 h kit build; Core One cannibalization of the enclosed case; P1S at ~$399–599 as the value pressure.

Prices (2026-09-21, via search)

• No fresh price surfaced. Standing: kit ~$799 / assembled ~$1,099. Re-verify live.

Coverage notes

• No new evidence this pass — the MK4S's evidence base (the strongest long-term signal in the batch) is unchanged. FB group gap persists; the community's real home is the Prusa forum anyway.