Mine bitcoin or buy it?
The question everyone asks when they see the power price: is a home miner worth it, or is it better to just buy bitcoin? This decider answers with the open math of frontier.py from mwhash — hashprice from primary data, a measured hashrate-rental premium, street rig prices. It opens with the answer for a typical Brazilian case; adjust tariff, rig, and scale.
Verdict
Buy. Home mining does not pay here.
At R$ 0,85/kWh, with 1× Antminer S21 Pro, producing bitcoin loses to simply buying. The best alternative to buying (Rent hashrate (HaaS)) would return −US$ 380/year vs DCA — and still require a power bill of R$ 2.148/month, 13× a typical home.
Where you mine
residential B1, all-in with taxes (ANEEL)
Which rig
234 TH/s · 3.51 kW · 15.0 J/TH · ~US$4.000 (new · air)
capex ~US$4.000 · 1 rig (home minimum)
Cost to produce 1 BTC
US$ 156.279
R$ 844 mil · energy + capex
2,5× the market price
Buy on the market
US$ 63.374
R$ 342 mil · just buy it
the bar to beat
Energy break-even
R$ 0,21
20,9 ct/kWh
mining only wins below this
Power bill / month
R$ 2.148
2.527 kWh · breaker ~20 A
13× a typical home (~200 kWh)
Buy vs mine vs rent — year-1 result, same money (capex of 1× Antminer S21 Pro = ~US$4.000)
| Strategy | Sats in year 1 | Net in year 1 | |
|---|---|---|---|
| Buy (DCA)spread+fees −1,0% once | 6.248.619 | −US$ 40−R$ 216 | |
| Self-mine1× rig · does NOT run at this tariff (only loses idle capex) | 0 | −US$ 1.333−R$ 7.200 | |
| Rent hashrate (HaaS)measured premium +10,6% + buy friction | 5.649.746 | −US$ 420−R$ 2.265 |
Mining only beats buying below R$ 0,21/kWh for the Antminer S21 Pro (20,9 ct) · renting (HaaS) with a positive premium: never beats buying. Rational operation: at a fixed tariff the rig runs all year or stays off (loss limited to idle capex).
Why buying almost always wins
The bill mining videos hide is electricity. At Brazilian residential retail (~R$ 0,85/kWh, all-in with taxes — ANEEL), the energy to produce 1 bitcoin costs more than twice buying one ready-made. The "naive" miner running 24/7 on the home tariff loses money — the same finding as the mwhash benchmark: the naive heat-miner loses. Grid fees are the moat between hobby and industry.
Mining only beats buying below the energy break-even shown above — curtailed, stranded, or behind-the-meter territory, where the kWh costs cents. Renting hashrate (HaaS) never beats buying: the marketplace premium is the seller's margin — measured at +10,6% on the NiceHash order book (2026-07-04). And BTC appreciation does not change the verdict: it benefits mining and buying equally, because both strategies end holding bitcoin.
Full method, data and versioned assumptions at github.com/matheusduartedm/mwhash — frontier.py, docs/viabilidade-mineracao.md, docs/haas-premium.md. Argue with the parameters, not vibes. Not financial advice.