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Bitmain Antminer S21 Pro (220-245 TH/s)
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Bitmain
Bitmain Antminer S21 Pro - 220-245 TH/s Bitcoin Miner BTC Mining
Bitmain Antminer S21 Pro - detail view 1 - Bitcoin miner
Bitmain Antminer S21 Pro - detail view 2 - Bitcoin miner
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Bitmain Antminer S21 Pro (220-245 TH/s)

2129
excl. taxes / incl. shipping
In stock, ready to ship
Available at short notice
No longer available
Only used available
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Minimum order quantity:
1
We have a minimum order quantity for this device in order to place it on our hosting site.
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Leasing from €10,000 (only in Germany)
  • 55 used units in stock in Hamm, Germany
  • €1,490 per unit, €1,390 when taking the entire stock

Variants & Prices

Delivery: In stock.

Quantity
Variant (power consumption)Cryptohall24
warranty		Manufacturer’s
warranty		Availability
Antminer S21 Pro 234 TH/s (3,510 W)SKU BTM-S21PRO-234TH€2,239€1,949In stock, ready to ship
Antminer S21 Pro 220 TH/s (3,300 W)SKU BTM-S21PRO-220TH€2,129€1,839In stock, ready to ship
Antminer S21 Pro 245 TH/s (3,675 W)SKU BTM-S21PRO-245TH€2,479€2,189Available at short notice

What the Cryptohall24 warranty covers: 12 months from purchase - if a device fails, you simply send it to us. We handle the entire process: initial diagnosis, shipping to the manufacturer, ticket management, final testing and return shipping to you. You deal with a German contracting party and a dedicated contact in your own time zone. With the manufacturer’s warranty only, you arrange air freight, import and export handling and the manufacturer’s ticketing yourself - the effort and the downtime risk stay with you.

Technical data

ManufacturerBitmain
ModelAntminer S21 Pro
AlgorithmSHA-256
CoinsBitcoin, Bitcoin Cash
Hashrate220-245 TH/s
Power consumptionapprox. 3,300-3,675 W
Efficiency15.0 J/TH
CoolingAir cooling
Dimensions (W x D x H)450 x 219 x 293 mm
Weight20 kg
Noise level76 dB

Description

The Bitmain Antminer S21 Pro is an air-cooled Bitcoin miner that Bitmain introduced in April 2024. It is built for the SHA-256 algorithm and can be used to mine Bitcoin or Bitcoin Cash. It comes in three performance levels between 220 and 245 TH/s, all with the same efficiency of 15.0 joules per terahash. The unit sits in the familiar Antminer housing with four fans, weighs 20 kilograms and runs on a single-phase supply of 220 to 277 volts.

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Performance levels of the Antminer S21 Pro

  1. S21 Pro 220 TH/s at 3,300 watts (BTM-S21PRO-220TH)
  2. S21 Pro 234 TH/s at 3,510 watts (BTM-S21PRO-234TH)
  3. S21 Pro 245 TH/s at 3,675 watts (BTM-S21PRO-245TH)

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The levels differ only in hashrate and power draw, the efficiency is identical across all of them. Bitmain states these figures as typical values: hashrate varies by up to three percent in operation, power draw and efficiency by up to five percent. Allow for this when sizing the power supply and circuit protection.

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Design, power connection and cooling of the S21 Pro

The housing measures 450 × 219 × 293 mm; packed for shipping the miner is 680 × 390 × 450 mm and weighs 22 kilograms. At 25 degrees intake air temperature Bitmain measures 76 dBA, so the unit is unsuitable for living or office space and belongs at a spot where the noise bothers nobody, or at a hosting site. Operation is approved between minus 20 and 45 degrees Celsius, storage between minus 20 and 70 degrees, at 10 to 90 percent humidity, non-condensing. Almost all of the power drawn leaves the unit as heat in the exhaust air, so at 3,300 to 3,675 watts per unit the exhaust has to be planned accordingly.

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The power supply is built in and rated at 4,000 watts, leaving headroom above the 3,675 watts of the top level. At the input the S21 Pro draws up to 20 amps at 50 to 60 hertz; an incorrect input voltage damages the unit. The miner connects to the network via RJ45 at 10/100 Mbit.

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The S21 Pro can also run custom firmware such as Braiins OS or Vnish. This lets you control the power per board, down for lower consumption or up for more hashrate, although efficiency drops slightly when overclocking. Bitmain locks newer units against flashing; since September 2025 a downgrade via SD card is required first. On request we install the firmware before shipping for 29.90 euros net per unit. This applies to units you operate yourself, not to miners in our hosting. Custom firmware voids the warranty, the manufacturer's as well as ours.

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As standard, Bitmain gives a 365-day factory warranty on the machine, counted from the shipping date; our standard price always includes our own warranty.

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Comparison with the previous and next generation of the S21 Pro

The predecessor is the Antminer S19K Pro, which Bitmain introduced in April 2023 as the last air-cooled miner of the S19 generation. The next generation is the Antminer S23, also air-cooled. The three units compared:

  • Antminer S19K Pro: 23.0 J/TH (120 TH/s at 2,760 W)
  • Antminer S21 Pro: 15.0 J/TH (220 to 245 TH/s at 3,300 to 3,675 W)
  • Antminer S23: 11.0 J/TH (318 TH/s at 3,498 W)

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Compared with the S19K Pro, the S21 Pro delivers almost twice the hashrate and needs around a third less power per terahash. Anyone replacing an S19K Pro fleet gets the same total hashrate with half the number of units. The S23 continues that path: at 11.0 joules per terahash it is another quarter more efficient than the S21 Pro. Within the S21 series, which began in October 2023 with the Antminer S21, the S21 Pro was the most efficient air-cooled unit from April 2024. In July 2024 the Antminer S21 XP followed at 13.5 J/TH, alongside various hydro units and immersion versions of the series. How the S21 Pro stacks up against every other unit in our range is shown in the miner comparison, ranked by daily yield.

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Verdict: Bitcoin mining with the Antminer S21 Pro

In our own operation and at our customers the S21 Pro runs very stably, and better than the previous generations. One reason is the thermal design: the housing has grown compared with the S19 series, and the larger fans move the heat out of the unit noticeably better.

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Since its launch we have seen very few defects on the S21 Pro, in our own hosting as well as on units our customers run themselves. When something fails, it is occasionally a hashboard. ASIC chips fail from excessive temperatures or hotspots, which happen when the unit is dusty and no longer cooled properly, or when the thermal paste no longer works well or has dried out. The boards are then repaired, not replaced. A repair on the S21 Pro is straightforward whatever the fault, and spare parts are readily available. Other operators in the mining market report the same very good stability: the units keep running and repairs are rare.

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Conclusion: the Antminer S21 Pro is a very good, solid unit from Bitmain that lasts, has good spare-parts availability and that we can fully recommend. If you are interested in the unit and want to run your own numbers, you can do so with our Bitcoin mining calculator. Yield depends on the Bitcoin network hashrate and the price, both shown live in the cockpit, as are the Bitcoin mining pools with their share and fees.

How the Purchase Process works

1
Request & Quote
You send us your inquiry, we come back with a binding quote and advise you on the right performance level. Once you confirm, we reserve the units.
2
Shipping & Import
Freight from Hong Kong, customs clearance and import VAT are handled by us. Before forwarding, we test every unit - you receive the machine cleared, taxed and tested.
3
Delivery or Hosting
We deliver to you, fully insured - or the machine goes straight to one of our hosting sites and is operated there under ideal conditions.
4
Commissioning
Pool, firmware, network: we set everything up together with you until the miner runs. We remain your point of contact - including in any warranty case.

Warranty provided by our German Company

When you buy mining hardware via Cryptohall24, you get a guarantee of 12 months In contrast to manufacturer warranties, our warranty only begins when the hardware is sold to our customers and not as soon as it leaves the factory. Since there can often be several months between production and sale in the mining market, our customers often have a longer effective protection than with the pure manufacturer's warranty.
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Optionally, the hardware can be added to insured for up to 36 months become.

Cryptohall24 employee providing technical support on an ASIC miner - Cryptohall24

Why Customers buy Miners from Cryptohall24

⌀ 4.8 / 5 stars
based on 135 Google reviews
Legally secure corporate structure according to German law
German contact person with personal support
Transparent prices with no hidden fees - with 12 months of warranty
Professional advice about mining hardware, hosting and profitability
Support with structural, tax and legal matters
Service Excellence through long-term partnership
FAQ
Do you have any questions?

How does buying a miner work?

The process is clear and done in a few steps: you enquire about the device you want, you receive a written quote with the final price from us, and as soon as you accept it, we issue the invoice. After full payment is received, we trigger the order and the hardware is on its way to you.

That way you know where you stand at every point - from quote to delivery, a continuously supported process with a personal contact.

How can I pay?

You can pay conveniently by bank transfer in euros, in crypto (Bitcoin or USDC) or in cash against a receipt.

As throughout our business, payment is in advance: we trigger the order as soon as payment has been received in full. That keeps the process clean and predictable for both sides.

Are there discounts for larger quantities?

Yes, discounts are possible for larger quantities. How large they are depends on several factors - the device, the quantity, the delivery location and the respective procurement conditions.

That's why we state the right price best directly in an individual quote. Just tell us the model and the quantity you want and we'll work it out for you.

What is included in the delivery?

On modern ASIC miners the power supply is built firmly into the machine and is therefore always included - it does not have to be bought separately. An external power supply only existed with very old first-generation models.

So you receive a ready-to-run device. Whatever else specifically belongs to the respective product is stated in the product description; in case of doubt we clarify it in the quote.

Is the miner in stock and how quickly is it delivered?

You can see availability directly on the product; in case of doubt we confirm it in the quote. The majority of our hardware is located in our main warehouse in Hong Kong and is shipped from there directly to your destination.

Individual devices are in stock in Germany (Hamm) - those reach you particularly quickly. We state the concrete delivery date bindingly in the quote, as soon as device and destination are clear.

How is it delivered - internationally and with customs clearance too?

We deliver worldwide. We handle the shipping and the complete import processing including customs clearance for you - you don't have to deal with it yourself. We state the shipping costs transparently in the quote.

That way the miner arrives ready to use at your place or the desired site. On request we deliver directly to our hosting, then the device goes into operation without a detour.

What requirements do I need for operation?

To operate at home or in your own business you mainly need three things: a suitable power connection (ASIC miners draw several kilowatts continuously, large devices often three-phase power), enough space with ventilation, and a stable internet connection via LAN.

On top of that come noise and waste heat: air-cooled devices are very loud and heat the room noticeably. Anyone who doesn't meet these requirements usually has the miner hosted - then we take care of power, cooling and operation.

How do I set up the miner and can I get help?

Commissioning is straightforward: connect the device, plug it into the network and configure it to your mining pool and wallet. After that the miner runs around the clock.

We don't leave you alone with it - we support you with setting up pool and wallet and the first steps, even without prior experience. Your personal contact is available for questions.

What warranty do I have on the device?

As a German company we offer you 12 months' warranty on your hardware as standard.

Alternatively, you can exclude the warranty in the purchase contract and handle it via the manufacturer's warranty - then the device becomes cheaper. We offer both routes; which one makes sense for you we clarify in the quote.

Can I have this miner hosted directly instead of running it myself?

Yes. You can buy the device from us and have it hosted in the same step - then it runs at a site with low-cost electricity, without noise and heat at your home.

For many this is the most economical way. You can read how hosting works on our hosting page.

As a business customer, can I cancel or return?

We sell our devices to businesses (B2B). A statutory consumer right of withdrawal therefore does not apply in B2B business; in addition, we procure and import the hardware specifically for your order.

So you buy in a targeted and binding way. That's exactly why we calmly clarify the right device for your project before the quote - so you make the right choice from the start. If you have questions before buying, we are always reachable.

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