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Bitmain Antminer S21+ 235T | High-Performance SHA-256 Miner

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Bitmain Antminer S21 Pro 245T – Efficient Bitcoin Miner

$4,200.00
A bare Antminer hashboard lying flat on a wooden floor, rows of heatsink strips facing up.
A bare Antminer hashboard lying flat on a wooden floor, rows of heatsink strips facing up, seen from directly above.

Bitmain Antminer S21 Pro 234T – Efficient SHA-256 ASIC Miner

Antminer S21 Pro 234T: 234 TH/s at 3,510 W, 15.0 J/TH, BM1370 chip, 220-277 V with the PSU built in. Same efficiency as the 220T and 245T variants – the difference is capital, not J/TH.

Price:

$4,200.00

Key specifications

Hashrate
234 TH/s ±3%
Power draw
3,510 W ±5%
Efficiency
15.0 J/TH
Input voltage
220–277 V AC — will not run on 120 V
Cooling
air, dual fans
Noise
roughly 75–76 dB
Full specification table
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Buying from ING Mining

  • Shipping$49.99 UPS GroundThe rate the checkout will charge on this item, read from the store’s own shipping settings rather than estimated. Ships from the US within 7 business days.
  • ConditionNewAs described on this listing.
  • GradingGraded before listingThis unit’s own grade is in the description above — where a listing states none, it says so. The six-step bench procedure behind a grade is published in full.
  • WarrantyStated per unit, not per storeAny term for this machine is in the description above. Ask for the return terms on this exact unit before you pay — full terms are in the Shipping & buying tab below.
Questions+1 (781) 577-0377 or ns@ingmining.com — who we are

Sold by ING Mining LLC — ING MINING® is a registered U.S. trademark.

Live Chat
  • Condition graded per unit: new, tested working, refurbished or as-is
  • Warranty and returns stated per unit, not per store
  • Ships UPS Ground within 7 business days

Description

The Antminer S21 Pro 234T is the mid variant of Bitmain’s air-cooled S21 Pro line: 234 TH/s at 3,510 W, which is 15.0 J/TH. It is the most common S21 Pro on the secondary market. Note that all three variants (220T, 234T, 245T) run at the same 15.0 J/TH — picking the smaller model saves capital, not electricity per terahash.

Specifications

Algorithm SHA-256 (Bitcoin, Bitcoin Cash)
Hashrate 234 TH/s ±3%
Power consumption 3,510 W ±5%
Efficiency 15.0 J/TH
ASIC chip Bitmain BM1370 (Bitmain does not officially publish the process node)
Input voltage 220–277 V AC — will not run on 120 V
Power supply built into the chassis, no separate power supply to buy
Cooling air, dual fans
Noise roughly 75–76 dB
Max operating temperature 45 °C
Manufacturer Bitmain

What’s in the box

  • 1 × Bitmain Antminer S21 Pro 234T
  • Nothing that is not listed above. Cords, controllers, brackets and spares are only included when this listing names them — if you need to know before you pay, ask on +1 (781) 577-0377 or ns@ingmining.com and we will confirm in writing what is physically in the crate

Published weights and dimensions vary between sources for this model. If you are booking freight or building racking, ask us and we will measure the actual unit.

What 15 J/TH means for your power bill

At 15.0 J/TH the S21 Pro covers its own electricity only below roughly 8.9 ¢/kWh at 10 August 2026 hashprice. Work that against your own power contract before you buy — the ASIC miner buying guide has the formula and the break-even table by model. We do not publish profitability figures; they move daily with difficulty and price.

Power and siting

3,510 W on a dedicated 220–277 V circuit at around 75 dB. Facility or hosted hardware, not a home machine.

Buying from ING Mining

Bitmain’s published warranty is 365 days from the shipment date and applies to the original direct purchaser, so on a resold unit support falls to the reseller. Ask us what we will cover and get it in writing. See also the S21 Pro 245T, the S21+ 216T, or everything in Antminer and all miners.

Before you weigh this against a used machine, work out your break-even power price rather than comparing sticker prices. The ASIC miner buying guide walks through the J/TH arithmetic, monthly kWh and what hosting genuinely costs.


The 234T runs the same 15.0 J/TH as every other S21 Pro. If you are weighing the family against Bitdeer’s current-gen air-cooled machine, our head-to-head comparison works through the repairability and warranty trade-offs that actually separate them.

Questions buyers ask about this machine

Will this run on a normal household outlet?

No. This machine needs a dedicated 220–277 V circuit. A North American 120 V household outlet will not run it under any adapter or configuration. At 3,510 W it draws about 14.6 A at 240 V, so the circuit wants a 20 A breaker — continuous loads are sized at 125% under the NEC, and a miner is the textbook continuous load. Size for your actual supply voltage, not ours: the same load on a 208 V feed draws more current, not less. Have an electrician confirm the supply before the pallet arrives.

What will it cost to run?

That depends on your electricity rate, so here is the part we can state exactly: at 3,510 W running 24/7, this machine burns about 2,527 kWh a month. Multiply that by your own all-in rate per kWh — including delivery charges, not just the supply rate — to get your monthly power bill. We do not publish profitability figures, because they change with difficulty and price every day.

How loud is it?

Roughly 75–76 dB — about as loud as a household vacuum cleaner running continuously, and it does not stop. This is a garage, workshop, outbuilding or hosted-facility machine, not something to put in a room where people live or sleep.

What can I mine with it?

The algorithm is SHA-256 (Bitcoin, Bitcoin Cash), and ASIC silicon is single-purpose: it will mine coins on that algorithm and nothing else, whatever the price of anything else does.

Is this a new unit?

Yes — new stock, as described in this listing. Any manufacturer warranty term that applies is stated in the description above; where none is stated, none is claimed.

Shipping cost for this exact item, and how warranty and returns work here, are answered in the Shipping & buying tab on this page. Anything else, ask a person on +1 (781) 577-0377 or ns@ingmining.com — we would rather talk before you buy.

Related hardware and where this sits in the store

Other air-cooled Antminer hardware at a similar duty:

Categories: Air Cooling, Bitmain Antminer, Bitcoin miner and New ASIC miners.



Where this listing sits

This one is on the new shelf. New stock, as described in the listing. Any manufacturer warranty term that applies is named in the description; where none is named, none is claimed.

What our grades mean

These are the only words we use, and each one means a specific thing. They are not interchangeable and we do not soften them to move stock.

NewUnused stock. Factory sealed unless the listing says otherwise — “new, open box” means exactly that, and the listing will say it.
Tested workingSecond-hand, and it ran on our bench at the hashrate the listing states. We measured it; we are not repeating what the last owner told us. Expect cosmetic wear.
RefurbishedTested working, plus work done: cleaned, thermal paste and fans dealt with, failed components replaced. The listing says what was actually done to that unit rather than using the word as decoration.
As-is / for partsSold with no working claim at all, at a price that reflects it. Buy these to repair or to harvest. If a listing says as-is, assume it does not hash until you have proved otherwise.
UntestedWe have it, we have not powered it, and we are not going to pretend we did. Rarer than as-is and always stated explicitly.

What a grade here does not mean

  • Cosmetic wear is not a fault. Dust, scratches, scuffed labels and discoloured plastics are normal on hardware that has been earning. We photograph what we have; if the pictures matter to you, ask for more and we will take them.
  • A grade is not a warranty. Warranty terms are stated per listing, never per store — see the Shipping & buying tab. A tested-working grade describes what the machine did on our bench, not what we owe you in six months.
  • A boosted hashrate is not a spec. Where a unit ships on tuned firmware we say so and we give the factory figures too, because overclocking raises power faster than it raises hashrate — a tuned machine is less efficient per terahash than stock, not more.
  • We will not invent a grade to fill a field. If a unit came in without history and has not been through the bench, its listing says that.

How the grade gets decided

A used-hardware seller who will not tell you how they test is asking you to take the grade on trust. Ours is published: the six-step bench procedure every machine goes through, and the five measurements that get recorded — per-board hashrate, chip count, measured wall power rather than the nameplate figure, hardware error rate, and temperature under sustained load. When it reaches you, run the 48-hour acceptance test straight away, while the freight claim window is still open.

Buying second-hand for the first time? How to buy a used ASIC miner without getting burned is the long version, written from the repair bench rather than from a spec sheet.

Shipping

Shipping this item inside the United States costs $49.99 by UPS Ground — that is the rate the checkout will charge, read from the store’s own shipping settings, not an estimate. Orders ship within 7 business days.

Outside the United States the checkout quotes a flat international rate. On multi-unit or pallet orders, contact us before ordering so freight to your destination can be confirmed properly. What to check when the pallet arrives, and how a freight claim works, is covered in the mining hardware shipping guide.

What to do the day it arrives

Photograph the pallet or the box before you open it, and keep the packaging until you are satisfied. Freight claim windows are short, and damage found on day two is a conversation while damage found on day thirty is an argument.

Then run the 48-hour acceptance test straight away, while that window is still open. It is the same ground our own bench covers, so you can compare like for like: how the grade on this listing was arrived at, and the five measurements we record, are set out in the Condition & grading tab on this page.

Condition, warranty and returns

Condition: New — as described on this listing.

Warranty is stated per listing, not across the catalogue. Some units carry a manufacturer term and say so above, naming the term and the date it runs from. Many units, particularly used and AS-IS stock, carry none, and those listings do not claim one. There is no blanket warranty covering a catalogue that runs from sealed factory stock to a hashboard sold for parts. For what a mining warranty normally covers, see ASIC miner warranty explained.

Returns: ask for the terms on this unit before you pay. No single returns window is published for the whole store, because the sensible terms on a tested working machine and on a board sold AS-IS for parts are not the same terms. Email or call and ask what applies to this exact item — it is a two-minute conversation and a great deal cheaper than a dispute.

Where you are going to run it

Two questions decide whether a machine like this works where you live, and neither of them is about the miner: can the circuit carry it, and what does your electricity cost? Most full-size machines here want a dedicated 240 V circuit and run at 70–75 dB continuously. A few do not — the Avalon Q publishes 45–65 dB and runs on 110–240 V — so read the voltage and noise figures on this listing rather than assuming. ASIC miner power requirements covers breaker sizing and what the install actually involves; cooling covers where the heat and the noise end up.

If your power is not genuinely cheap, hosting is the question to be asking instead of which miner to buy. Break-even electricity rate is hashprice divided by (24 × J/TH), and hashrate cancels out of it entirely — which is why a cheap old machine on expensive power loses money faster than an expensive new one does. The buying guide has the arithmetic; work out your own number before you buy anything.

If hosting is the answer, get written answers on three things before you sign: who pays for repairs, what the uptime commitment actually pays out when it is missed, and how curtailment is handled. A flat per-machine monthly rate is where most of the unpleasant surprises live. Types of mining farm compares the models and hosting versus cloud mining covers why owning the hardware is the better end of that trade. Ask us before you commit — it is a five-minute call and a great deal cheaper than a contract you cannot get out of.

What we do once it is racked, wherever that is. Deployment, firmware and monitoring are a service we run rather than a line on a page: pool and network setup, Braiins OS or VNish tuning, offline alerts, and board-level fault-finding when a machine stops hashing — ASIC mining consulting sets out what that covers. The hosting agreement itself is between you and the facility. What we can give you is the number most hosting disputes turn on: what this machine measured at the wall on our bench, so a shortfall on site is a figure to compare against rather than an argument about what it should have been doing.

Who you are buying from

ING Mining LLC, Hanson, Massachusetts. ING MINING® is a registered U.S. trademark; our marketplace feedback is on the reviews page and the longer version of who we are is on about. Reach a person on +1 (781) 577-0377 or ns@ingmining.com.

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