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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

$4,200.00
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Bitmain Antminer S21 XP 270T – Efficient Bitcoin Miner

$399.99
Ten Antminer power supply units arranged in two rows on a speckled shop floor, photographed from the left.
A bare Antminer hashboard lying flat on a wooden floor, rows of heatsink strips facing up.

Bitmain Antminer S21 Pro 245T – Efficient Bitcoin Miner

Antminer S21 Pro 245T: 245 TH/s at 3,675 W, 15.0 J/TH, BM1370 chip, 220-277 V with the PSU built in. Air-cooled at around 75 dB, so it is a facility machine rather than a home one.

Price:

$4,200.00

Key specifications

Hashrate
245 TH/s ±3%
Power draw
3,675 W ±5%
Efficiency
15.0 J/TH
Input voltage
220–277 V AC — will not run on 120 V
Cooling
air — published fan counts disagree for this model, with both two and four quoted
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 245T is Bitmain’s high-hashrate air-cooled SHA-256 machine: 245 TH/s at 3,675 W, which is 15.0 J/TH. All three S21 Pro variants (220T, 234T and 245T) share that same 15.0 J/TH efficiency — the bigger models simply run more silicon harder, they are not more efficient per terahash.

Specifications

Algorithm SHA-256 (Bitcoin, Bitcoin Cash)
Hashrate 245 TH/s ±3%
Power consumption 3,675 W ±5%
Efficiency 15.0 J/TH
ASIC chip Bitmain BM1370
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 — published fan counts disagree for this model, with both two and four quoted
Noise roughly 75–76 dB
Max operating temperature 45 °C
Manufacturer Bitmain

What’s in the box

  • 1 × Bitmain Antminer S21 Pro 245T
  • 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, dimensions and even fan counts for this model vary between sources (both 400 × 195 × 290 mm and 450 × 219 × 293 mm are quoted, and both two and four fans). If you are booking freight or building racking, ask us and we will measure and weigh the actual unit rather than repeat a spec sheet.

What 15 J/TH means for your power bill

At 15.0 J/TH this machine covers its own electricity only below roughly 8.9 ¢/kWh at 10 August 2026 hashprice. That is the number that decides whether it makes sense for you, and it has nothing to do with the terahash figure. Our ASIC miner buying guide gives you the one-line formula so you can check it against your actual power contract. We do not quote profitability figures, because they change with difficulty and Bitcoin price every day.

Power and siting

3,675 W on a dedicated 220–277 V circuit, and around 75 dB. This is a warehouse or hosted-facility machine, not a home one. If you want something you can live beside, the Avalon Q is the honest recommendation instead.

Repairability

The BM1370 has a real independent parts market and S21-family hashboard repair is a service several shops advertise, which is a genuine advantage over newer non-Bitmain hardware. We stock Antminer repair parts, testers and fixtures ourselves.

Buying from ING Mining

Bitmain publishes a 365-day warranty running from the shipment date, and it runs to the original direct purchaser — on a resold machine, support is the reseller’s responsibility. Ask us what we will cover and for how long, and we will confirm it in writing before you order. Compare it against the Bitdeer SealMiner A2 Pro Air, or browse Antminer and the full catalogue at all miners.

At 15 J/TH, an S21 Pro covers its own electricity only below roughly 8.9¢/kWh at 10 August 2026 hashprice. Our ASIC miner buying guide gives you the one-line formula so you can check that against your actual power contract before you order.


Cross-shopping this against the Bitdeer SealMiner A2 Pro Air? The two are within 1% of each other on efficiency, so the decision comes down to parts, warranty and resale. We put both side by side in S21 Pro vs SealMiner A2 Pro Air.

Cross-shopping this against cheap used hardware instead? The capital gap is large enough that a used S19 XP pays back faster below roughly 5.5¢/kWh, while the S21 Pro keeps earning at rates that shut the older machine off entirely. Both cases are worked through in Antminer S19 XP vs S21 Pro.

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 3,675 W it draws about 15.3 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 3,675 W running 24/7, this machine burns about 2,646 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.

The same $4,200 buys nine used S19k Pros — when to buy this instead

Priced per terahash this machine loses badly, and we would rather show you that than have you find it out: the same money, freight included, buys nine used Antminer S19k Pros and four times the hashrate.

  One new S21 Pro 245T Nine used S19k Pros
Goods $4,200.00 $3,419.91
Freight at $49.99 a unit $49.99 $449.91
Landed $4,249.99 $3,869.82
Hashrate 245 TH/s 1,035 TH/s
Landed cost per TH/s $17.35 $3.74
Wall power 3.7 kW 23.8 kW
20 A / 240 V circuits 1 9
Hashboards in service 3, new 27, used

The case for this machine is not capital. It is everything in that table that scales with the number of boxes: one 20 A, 240 V circuit instead of nine, 245 TH/s per breaker against 115 — 2.1 times the terahash per slot — three new hashboards instead of twenty-seven used ones, 3.7 kW of heat instead of 23.8 kW, and a manufacturer warranty term for the first year rather than a tested-working claim. On electricity there is a crossover near 5.1 cents a kilowatt-hour: below it the used fleet nets more, above it this machine does, and a little higher again it is the only one of the two still earning anything. The full arithmetic, both baskets, is here.

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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