26 Rigs, One Cheap OPEX: 2025’s Definitive Ranking of Modern Bitcoin Miners

At an operating expense of $0.04 per kilowatt-hour (kWh), the current crop of SHA256 bitcoin miners sorts into a clear profit ladder, with high-hashrate hydro units setting the pace and a few efficient air and immersion options keeping things interesting.

The Four-Cent Test: Which Bitcoin Mining Rigs Still Shine

The king of the hill at this power price is Bitmain’s Antminer S23 Hydro 3U, rated at 1,160 TH/s with about 11,020 W on the wall, printing roughly $50.06 per day.

It is the classic “throw hash at it” approach: immense throughput, sensible power for the class, and a daily take that sets our benchmark for everything that follows. Nevertheless, the S23 Hydro 3U will not reach buyers until January 2026.

The runner-up is Bitmain’s Antminer S21e XP Hydro 3U at 860 TH/s and 11,180 W, bringing in $34.23/day using today’s BTC prices. While its efficiency trails the S23 Hydro 3U on a pure TH/s-per-watt basis, it still delivers a strong daily dollar figure; when cheap power meets lots of hash, physics and math shake hands.

Third place goes to the Proto Rig at 819 TH/s and a stout 12,000 W, good for $31.30/day. It’s the quintessential custom-class brute created by Block: a touch hungrier than the leaders, but the hashrate keeps it in the top tier. If the electrical capacity is available, the unit’s higher draw translates into proportionally higher daily output.

The Bitdeer Sealminer A3 Pro Hydro takes our fourth slot with 660 TH/s, 8,250 W, and $26.58/day. Its mix of hydro cooling and measured power draw makes it a compelling mid-top option. Right behind it, Bitmain’s Antminer S23 Hydro (non-3U) clocks 580 TH/s at just 5,510 W and nets $25.03/day, a reminder that not every high earner needs a four-figure TH/s badge to compete.

Auradine’s Teraflux AH3880 adds variety to the podium crowd: 600 TH/s, 10,740 W, and $21.06/day. It delivers consistent output at four-cent power, placing it in line with comparable units. The unit highlights how efficiency and wattage draw create narrow margins that separate mid-tier machines.

Bitmain’s Antminer S21 XP+ Hydro follows with 500 TH/s at 5,500 W, producing $20.86 per day. Close behind, Bitdeer’s Sealminer A3 Hydro delivers the same 500 TH/s but with a higher 6,750 W draw, resulting in $19.66 per day. The comparison illustrates how identical hashrates can yield different returns once efficiency is factored in.

The Bitmain Antminer S21 XP Hydro at 473 TH/s and 5,676 W follows at $19.28/day. From there, Bitdeer’s Sealminer A2 Pro Hydro shows 500 TH/s at 7,450 W and $18.99/day—a touch thirstier than the A3 Hydro at the same hashrate, but still solid at this OPEX. Bitmain’s Antminer S23 Immersion (442 TH/s, 5,304 W) adds $18.02/day, a nice “cool and quiet” option where immersion is the standard.

Mid-pack starts to compress. Canaan’s Avalon A1566HA 2U posts 480 TH/s at 8,064 W for $17.35/day, and MicroBT’s Whatsminer M63S++ matches the daily figure—464 TH/s, 7,200 W, $17.35/day. One draws a bit more power for slightly higher TH/s; the other leans on efficiency. Either way, at four-cent power, they land on the same daily dollar.

Bitmain’s Antminer S21e XP Hydro at 430 TH/s and 5,590 W delivers $17.11/day. The older but still relevant Antminer S19 XP Hydro 3U logs 512 TH/s and 10,600 W for $16.59/day, proof that legacy hydro boxes remain viable when electricity is cheap and uptime is disciplined.

Bitdeer’s Sealminer A2 Hydro (446 TH/s, 7,360 W) slots in at $16.25/day. MicroBT’s Whatsminer M63S+ follows—424 TH/s, 7,208 W, $15.25/day—marking the point on our ladder where power starts to pinch. Still, at $0.04/kWh, even these units maintain respectable daily returns when run continuously.

From here, the field turns into a clinic on efficiency trade-offs. Bitmain’s Antminer S21+ Hydro at 358 TH/s and 5,370 W yields $13.56/day; MicroBT’s Whatsminer M63S lists 390 TH/s, 7,215 W, $13.46/day; and MicroBT’s Whatsminer M66S++ at 356 TH/s and a notably lower 5,518 W lands $13.31/day. The pattern is clear: trim watts, defend profit.

Bitmain’s Antminer S23 (air-cooled) posts 318 TH/s at just 3,498 W for $13.27/day—a reminder that sensible wattage can keep smaller-hash rigs in the conversation. Bitmain’s Antminer S21 Hydro at 335 TH/s and 5,360 W yields $12.37 per day, placing it among the mid-tier machines where efficiency and hashrate balance against electricity costs

Auradine’s Teraflux AI368Q clocks 360 TH/s, 6,840 W, and $12.25/day. Bitmain’s Antminer S21+ Hydro (the 319 TH/s variant) trims to 4,785 W and nets $12.08/day. These units show consistent power use and output, with performance figures that remain stable when compared across larger operational groups.

The Antminer S21 XP Immersion at 300 TH/s and 4,050 W returns $11.80/day, while Bitdeer’s Sealminer A3 Pro Air rounds out our list at 290 TH/s, 3,625 W, and $11.68/day. Air still has a place—especially where water and immersion are impractical—but at this OPEX, hydro and immersion tend to keep a small edge.

Bitmain’s Antminer S9 series, once the backbone of global hashpower before 2019, now operates at a loss—even with electricity priced at $0.04 per kilowatt-hour. Units like the S9 SE, S9i, S9j, and the S9 Hydro all generate negative returns, with daily losses from $0.39 to $0.72. Once the industry’s defining workhorse, the S9 family today serves more as a relic of bitcoin mining’s past than a viable option.

What jumps out across all 26 models (not including the S9s) is how the hydro-cooled class has seized the upper rungs. The very top is a hashrate story—the S23 Hydro 3U’s 1,160 TH/s can bulldoze variance when it drops in January—but the mid-table is an efficiency story, where sub-7 kW rigs with 300–500 TH/s hang surprisingly close on daily dollars. Cheap power lets sheer hash win; practical power budgets keep the efficient units in the money.

Another takeaway: parity moments are real. The Canaan Avalon A1566HA 2U and MicroBT Whatsminer M63S++ both printing $17.35/day show how different design choices can converge at a given electricity price. For operators, that means procurement can factor in availability, warranty, and fleet standardization without giving up profit—handy in a market where supply timing is half the game.

Mixing vendors also hedges risk. A lineup that spans Bitmain’s S23/S21 families, Bitdeer’s Sealminer A-series, MicroBT’s M63/M66 units, Auradine’s Teraflux models, a Canaan Avalon anchor, and even a custom-style Proto Rig from Block helps a farm navigate parts, firmware, and logistics across cycles. At $0.04/kWh, the math supports diversity without sacrificing much at the meter.

In short, at a four-cent OPEX threshold, the profit ladder is topped by high-throughput hydro gear—the upcoming Bitmain Antminer S23 Hydro 3U—with a tightly packed midfield where efficiency keeps the lights just as green. From the S21e XP Hydro 3U and Proto Rig down to the Sealminer A3 Pro Air, every model here can pull its weight; the right choice for your rack depends on amps, aisle, and appetite.