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Machine review · Oct 18, 2026 · 4 min read
Whatsminer M61S+ review: 17 J/TH in an air-cooled box at the best entry price it has had
MicroBT's M61S+ is an air-cooled machine that makes a bitcoin on 17 J/TH, with 232 TH/s in a single unit. It clears its power at 6¢ with room today, and at its lowest price per terahash yet it is a sound way to add hashrate. Cheaper power is where it pays most.
MicroBT Whatsminer M61S+ (232 TH/s)
The bottom line
The M61S+ is MicroBT's air-cooled Whatsminer from the late-2024 M61 line: 232 TH/s from 3,944 W in the bin we stock, 17 J/TH. At our Argentina site, at 6¢, it makes a bitcoin for about $56,100 of electricity and returns roughly 31% in its first year at today's price. At Nigeria's 3.9¢ the same coin costs about $36,400.
Bought the week we first held a price for it, in August 2025, it has mined and kept 0.0438 BTC for $2,392 of power: $1,177 of cashflow against a $4,912 landed cost, which is what the first months of a four-year machine look like. Between now and the 2028 halving it has another 0.045 BTC in it, worth about $5,574 with bitcoin back at its previous high: roughly 1.4× its hardware by the halving, with the machine still running afterwards.
What you are buying is a lot of hashrate in one air-cooled unit, at $7.14 a terahash, the lowest price per terahash it has had. What you are not buying is the best return: the S21+ costs $6.72 a terahash and returns about 34% in year one in the same hall, against this machine's 31%.
Scores
| Criterion | Score | Why |
|---|---|---|
| Cashflow | 5.5/10 | Makes a bitcoin for about $56,100 of electricity at 6¢ and returns roughly 31% in year one at today's price. It is on track for about 1.4× its hardware by the 2028 halving. The S21+ returns about 34%. |
| Longevity | 5/10 | At 17 J/TH its line is $24.48 a petahash a day at 6¢ and $15.91 at 3.9¢. Hashprice halved, $19.46, sits between the two, so after the halving it is a Nigeria machine, which is the move every machine makes once. |
| Efficiency | 4.5/10 | A fair figure for the 2024 generation and a modest one now: the S21 XP and the M70S run 13.5 J/TH in an air-cooled box, and the M60S++ runs 15.5. |
| Quality control | 5/10 | Scored as unknown rather than as good. We found no operator reports of the M61S+ in the field that we could cite. |
| Serviceability | 6.5/10 | An air-cooled unit with no water loop to service. Hosted with us in Argentina, a fault is a parts bill and a line item. |
Cashflow and efficiency count most, because they decide how many halvings a machine survives; reliability is scored as unknown, not as good, because we found no failure record to cite.
Buy it if
- You want 232 TH/s in one air-cooled unit and a MicroBT machine in an air-cooled hall, at $1,656 for the unit.
- Your power is at or below 6¢. At 6¢ it makes a coin for about $56,100; at 3.9¢, about $36,400.
- Your power is between 6¢ and 7¢. Its line at 7¢ is $28.56 a petahash a day, under today's hashprice of $38.92 and just above the $27.74 low of last June, so it still clears today with less room.
- You expect to cross to Nigeria once, when the figures say so. At 17 J/TH its line there is $15.91 a petahash a day, well under today's hashprice.
Walk away if
- Your power is between 7¢ and 8¢ and you want room at a hashprice like June's. At 8¢ its line is $32.64 a petahash a day; above 8¢, choose a more efficient machine.
- You are planning past 2028 at 6¢. Its line there is $24.48 a petahash a day, and today's hashprice halved is $19.46, so those years lean on bitcoin recovering.
- You want the most return per dollar. The S21+ returns about 34% and the S21 Pro about 35% in year one, against this machine's 31%.
- You want a long public failure record. We found no operator reports of the M61S+ that we could cite, so we score that as unknown.
232 TH/s in an air-cooled box, one step above the M61S
MicroBT announced the M61S+ with the rest of its December 2024 range: Forklog reported it on 9 December 2024 as “The air-cooled WhatsMiner M61S+ (236 TH/s)”. Our store lists bins from 232 to 242 TH/s, and the figures in this review are the 232 TH/s bin at 3,944 W, which is our store record. We could not open MicroBT's own page for it, so dimensions, weight and noise are left out rather than guessed.
It is a step above the M61S. The M61S runs 18.5 to 20 J/TH in our store and the M61S+ runs 17, so a unit that draws about 4 kW returns noticeably more hashrate. The M60S+ has the same 17 J/TH in a 206 TH/s unit, so the M61S+ gives 13% more hashrate per unit at the same efficiency. A year in, the Whatsminer M61S has crossed to Nigeria shows where the first step of this line ended up.
What a coin costs it
At 6¢ in Argentina it makes a bitcoin for about $56,100 of electricity today, against a bitcoin price of $81,897. At Nigeria's 3.9¢ the same machine makes one for about $36,400. The S21 XP makes one in Argentina for about $44,500, the M70S for about $44,500, the S21 Pro for about $49,500 and the S21+ for about $54,400.
In its first year the M61S+ returns about 31%. The S21+ returns 34%, the S21 Pro 35%, the S21 XP 33% and the M60S++ 30%. The M61S+ is at the bottom of that group, which is where 17 J/TH puts a machine once the S21s are in the room.
Over its run since August 2025, electricity has averaged about $54,700 a coin. That is a short lifetime average; the figure to plan on is today's.
Its price per terahash is the lowest it has had
The first price we hold for the unit, on 21 August 2025, was $13.97 a terahash. From March to July 2026 it sat between $8.71 and $9.26, and in September it was between $7.04 and $7.14. It is $1,656 today, $7.14 a terahash, for the same 232 TH/s at the same 17 J/TH. That is the best entry price the machine has had, and the hashrate it buys is the hashrate it always was.
Against the other air-cooled machines we stock it is cheap per terahash and middling on efficiency. The S21 XP, at 13.5 J/TH, is $11.55 a terahash and the M70S $12.60. The M60S++, at 15.5 J/TH, is $9.45. The S21 Pro, at 15 J/TH, is $8.61, and the S21+, at 16.5 J/TH, is $6.72. What sits on top of the box is in the guide to what a miner costs all-in.
Where the halving puts it
A machine's line is the hashprice at which it stops covering its own power. At 17 J/TH a petahash uses 408 kWh a day: $24.48 at 6¢, and $15.91 at Nigeria's 3.9¢. Network hashprice was $38.92 a petahash a day on 18 October on our hashprice chart, so the M61S+ clears the 6¢ line with room. It also cleared it at the year's low of $27.74 on 6 June.
The 2028 halving halves the coins a petahash earns. At today's price and difficulty that puts hashprice near $19.46, under the 6¢ line and above the Nigerian one. That is today's conditions held flat, not a forecast: it is why every projection we publish assumes the old high returns, and the forward figures here do the same.
A 13.5 J/TH machine has a line of $19.44 at 6¢, which is about that halved level, and that is the case for the S21 XP or the M70S if you plan to stay in Argentina. The M61S+ is a different bet: an Argentina machine now and a Nigeria machine after the halving, with the move made once. The guide to crossing once explains why, and the guide to efficiency and halvings shows where the line sits at every J/TH.
At 17 J/TH a petahash uses 408 kWh a day: $24.48 at 6¢ and $15.91 at Nigeria's 3.9¢.
What a fault costs you here
We looked for operator threads and repair write-ups on the M61S+ and found nothing specific to it that we could stand behind, so quality control is scored as unknown. That is a gap in the record, not a finding about the machine: it was announced in December 2024 and a public failure record for it has not built up yet.
What a fault costs is the part that matters. Hosted with us in Argentina, a repair is billed at the cost of the parts and nothing else, and it is a line item, not a catastrophe. An air-cooled unit has no water loop to service, which keeps that bill short.
We found no operator reports of the M61S+ we could cite. We score that as unknown, not as good.
Our two cents
The M61S+ is a sound machine at the lowest price it has had. It clears its power at 6¢ today with room, it puts 232 TH/s in one air-cooled unit, and the one move it will make, to Nigeria, is where its figures improve most: a coin there costs about $36,400 to make.
If the aim is the most return on the money, the S21+ and S21 Pro show higher first-year returns today, at $6.72 and $8.61 a terahash. If the aim is the cheapest coin, the S21 XP makes one for about $44,500 at the same site. The figure below ranks what beats this machine on cost per coin and then on first-year return, in stock today. A coin that costs less to make is a coin you keep more of.
- MicroBT Whatsminer M74S+ (332 TH/s) — 12 J/TH, In stock, $39,573 of electricity per bitcoin, 31% year one
- MicroBT Whatsminer M73S (560 TH/s) — 13 J/TH, In stock, $42,870 of electricity per bitcoin, 36% year one
- MicroBT Whatsminer M70S (260 TH/s) — 13.5 J/TH, In stock, $44,519 of electricity per bitcoin, 30% year one
Sources and further reading
- MicroBT unveils new line of bitcoin miners — Forklog, 9 Dec 2024
Which machines this covers
Disclosure
Firsthand Bitcoin sells and hosts mining hardware, including this machine. No manufacturer, distributor or affiliate programme paid for or reviewed this page and we take no commission on the links above. Historical figures are computed from daily bitcoin price and network hashprice, each day valued at its own prices. Nothing here is investment advice.