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Enterprise Guide November 2026 • 8 min read

Antminer S21 Series: Enterprise Fleet Guide

Bitmain Antminer S21 series compared for enterprise fleets on verified hashrate, efficiency and price, air to hydro and immersion — request a quote today.

#Hardware #Enterprise #Bitmain

The Bitmain Antminer S21 series is the workhorse of Bitcoin mining, spanning 190 TH/s to 500 TH/s across air, hydro and immersion cooling, and this guide compares all ten models on verified specs so a fleet plan can be priced before it is ordered. The efficiency leader is the S21 XP+ Hyd at 11.0 J/TH, the cheapest cost per terahash is the S21+ Hyd at $9.22 per TH/s, and the air-cooled standard is the S21 Pro at 234 TH/s and 15.0 J/TH. Choose the model that fits your power price and cooling, not simply the largest hashrate.

Antminer S21 Series at a Glance

The S21 series is the range most enterprise buyers actually deploy at scale. It covers every cooling type a site is likely to run, from standard air-cooled halls to dense hydro halls and fanless immersion tanks, and every model runs SHA-256 for Bitcoin with a 12-month warranty. Prices run from $1,990 for the entry-level T21 to $9,500 for the 500 TH/s S21 XP+ Hyd. No single model is right for every site: the correct pick depends on power price, cooling and rack space.

What the range covers

• Three air-cooled models from 190 TH/s to 234 TH/s on standard 200 to 240 V power.
• Five hydro-cooled models from 288 TH/s to 500 TH/s on 380 to 415 V three-phase power.
• Two immersion models at 239 TH/s and 300 TH/s, fanless at 0 dB for tank farms.
• One efficiency leader, the S21 XP+ Hyd at 11.0 J/TH, and one value leader, the S21+ Hyd at $9.22 per TH/s.
• Nine of the ten models in stock; the S21e Hydro is pre-order, and the S21 Pro is held ready in the US warehouse.

Air-Cooled S21 Models: The Standard Hall Fleet

Air-cooled S21 miners suit operators that want machines running days after delivery, on power that most industrial sites already have. The trade-off is noise: the full-size air models run at 75 dB, so hearing protection belongs on the walk-round checklist. For a first fleet, or for a hall that cannot justify a hydro retrofit, air cooling is the fastest and cheapest deployment path.

The flagship: Antminer S21 Pro

The S21 Pro is the air-cooled standard of the series: 234 TH/s at 3,510 W and 15.0 J/TH, priced at $3,490, or $14.91 per TH/s. It is held ready in the US warehouse, runs on 200 to 240 V power, and weighs 15.4 kg. At 15.0 J/TH it is the most efficient air-cooled S21, and its daily electricity cost is $6.74 per unit at $0.08 per kWh. Buyers who need air cooling and want the lowest operating cost per terahash in the series should start here: the full listing is on the [Antminer S21 Pro product page](/product/antminer-s21-pro-234t).

The value picks: Antminer S21 and T21

The base Antminer S21 delivers 200 TH/s at 17.5 J/TH for $2,890, or $14.45 per TH/s, and the T21 delivers 190 TH/s at 19.0 J/TH for $1,990, or $10.47 per TH/s. The T21 is the cheapest entry point into the series, but it is also the least efficient, so its daily electricity cost per TH/s is the highest of the air range at $0.0365. The rule is simple: if power is cheap, the T21's low purchase price wins; if power is expensive, the S21 Pro's 15.0 J/TH pays back the premium.

Hydro and Immersion S21 Models: Liquid-Cooled Density

Hydro-cooled S21 miners are built for sites that already run, or plan to build, a liquid loop. Direct-to-chip cold plates move heat into water instead of air, cutting noise to 40 to 50 dB and packing far more hashrate into each rack position. The cost is infrastructure: every hydro model needs 380 to 415 V three-phase power, a manifold and a dry cooler, so the buying decision must include the hall, not just the miner. The [turnkey infrastructure](/infrastructure) options cover that side of the build. Immersion models go further: factory-built for dielectric tanks, they run fanless at 0 dB, at the cost of a tank farm and approved fluid.

The efficiency leader: S21 XP+ Hyd

The S21 XP+ Hyd is the most efficient machine in the S21 series: 500 TH/s at 5,500 W and 11.0 J/TH, priced at $9,500, or $19.00 per TH/s. It is the newest model in the range, released in the fourth quarter of 2025, with the lowest daily electricity cost in the series at $0.0211 per TH/s at $0.08 per kWh. The premium per terahash is real, so this model suits operators paying higher power prices, where efficiency savings compound daily.

The volume hydro picks: S21 Hyd, S21+ Hyd and S21e Hydro

The S21 XP Hydro delivers 473 TH/s at 12.0 J/TH for $8,450, or $17.86 per TH/s. The S21+ Hyd, released in the third quarter of 2025, delivers 358 TH/s at 15.0 J/TH for $3,300, or $9.22 per TH/s, the cheapest cost per terahash in the series and the strongest value pick for a hydro hall buying in volume. The S21 Hyd and S21e Hydro fill out the range at $13.40 and $13.85 per TH/s; the S21e Hydro is pre-order.

The immersion pair: S21 XP Immersion and S21 Immersion

The S21 XP Immersion delivers 300 TH/s at 13.5 J/TH for $5,990, or $19.97 per TH/s, and its factory warranty is valid in approved immersion fluids. The S21 Immersion delivers 239 TH/s at 16.0 J/TH for $3,290, or $13.77 per TH/s. The XP Immersion is the efficiency pick for a tank farm, while the S21 Immersion is the value pick: at $13.77 per TH/s it is cheaper per terahash than any air-cooled S21 except the T21. Confirm fluid compatibility and tank capacity before ordering.

Daily Electricity Cost: Where the Range Separates

Daily electricity per terahash is efficiency multiplied by 0.024 kWh and by the power price: at $0.08 per kWh, J/TH times $0.00192. These are electricity costs only: revenue depends on network difficulty and the Bitcoin price, which move daily, so no income or payback figure is stated here. Model revenue against these costs with the [mining calculator](/calculator) at your own power price.

A 10 PH/s fleet built from the S21 XP+ Hyd needs 20 units, drawing 110.0 kW and costing $190,000. The same capacity from the S21 Pro needs 43 units, drawing 150.9 kW and costing $150,070. From the S21 Hyd it needs 30 units, drawing 160.8 kW and costing $134,700. The cheapest fleet to buy draws the most power; the most efficient fleet costs the most to buy.

Choosing an S21 Fleet for Your Site

Start from power and cooling, then pick the model. A standard hall on single-phase power points to the S21 Pro where power is expensive, or the T21 and S21 where budget is tight and power is cheap. A three-phase hall with a liquid loop points to the S21 XP+ Hyd for efficiency or the S21+ Hyd for the cheapest cost per terahash. A tank farm points to the immersion pair for silent, dust-free operation.

Who this guide is for, and who it is not for

This guide is for data centre operators, institutional buyers and fleet owners choosing SHA-256 capacity. It is not for buyers choosing between algorithms, where J/TH cannot be compared across coins, and it is not a revenue forecast: no figure here promises income. It is also not for buyers who need the lowest efficiency available: the S23 family reaches 8.9 J/TH and should be priced alongside any large S21 order.

Which Antminer S21 is the most efficient?

The S21 XP+ Hyd at 11.0 J/TH, followed by the S21 XP Hydro at 12.0 J/TH and the S21 XP Immersion at 13.5 J/TH. The most efficient air-cooled model is the S21 Pro at 15.0 J/TH.

Which Antminer S21 is the cheapest per TH/s?

The S21+ Hyd at $9.22 per TH/s, followed by the T21 at $10.47 and the S21 Hyd at $13.40.

Is the S21 Pro still worth buying with the S23 family available?

For air-cooled halls, yes: the S21 Pro is in stock, held in the US warehouse, and costs $14.91 per TH/s. For high power prices or a new liquid-cooled hall, price the S23 family's 8.9 J/TH in the same comparison.

What should I confirm before ordering?

Hashrate and allocation for the model you want, your site's power type and capacity, the cooling design, warranty length, and freight terms to your destination. One clear next step: shortlist from the tables above, run each candidate at your power price, and request a quote stating hashrate, power price, cooling status and destination.

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