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Progress report · Sep 10, 2026 · 5 min read

Eighteen months with the Antminer S21+, and where it goes next

On track to cover its hardware well before the halving, and at the best entry price it has ever had. Here is what it has done so far and what the next two years look like.

Bitmain Antminer S21+ (225 TH/s)

What it has done so far

A 225 TH/s S21+ at 16.5 J/TH, bought at $3,308 and landed at $4,685, and racked in Argentina at 6¢ in April 2025. In 575 days it has mined and kept 0.0599 BTC, worth about $4,631 today, for $3,143 of electricity — about $52,500 a coin.

That is $1,488 of cashflow and roughly 32% of its landed cost — about where a machine should be this early in a four-year working life. All 575 of those days have been in Argentina at 6¢, and it is still clearing there with room. The move to cheaper power is something this machine has ahead of it, not behind it.

The next two years

At today’s difficulty and with bitcoin back at its previous high, the S21+ has another 0.038 BTC and roughly $4,674 in it between now and April 2028. Added to what it has already banked, that puts it near 1.3× its full landed cost by the halving — hardware, freight, duty, customs and setup all covered, with the machine still running.

And it will still be running. At 16.5 J/TH it clears comfortably at 6¢ today and will still clear at 3.9¢ well past 2028, which is the test most hardware fails. Our Nigeria site is where that second act happens, and it is measured in years rather than months.

The hard part is behind it. Everything from here is the flatter, longer half of the curve.

The entry price does the work

A buyer today gets the same 225 TH/s at 16.5 J/TH for about $1,488, which is why its first-year return at our rates is about 22%. The machine produces exactly what it always did.

That is the pattern worth internalising. Buying a proven machine a year or two into its life, once its price has settled, is one of the few genuinely free improvements available in this business.

• MicroBT Whatsminer M74S+ (332 TH/s) — 12 J/TH, In stock, $42,565 of electricity per bitcoin, 24% year one
• MicroBT Whatsminer M73S (560 TH/s) — 13 J/TH, In stock, $46,113 of electricity per bitcoin, 27% year one
• MicroBT Whatsminer M70S (260 TH/s) — 13.5 J/TH, In stock, $47,886 of electricity per bitcoin, 23% year one

Which machines this covers

• Bitmain Antminer S21+ (225 TH/s)
• Bitmain Antminer S21+ (235 TH/s)
• Bitmain Antminer S21+ (216 TH/s)

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.