The Antminer S21 Pro 234 TH/s variant uses approximately 84.24 kWh per day at its manufacturer-rated typical wall power of 3,510 W and continuous operation. In the illustrative scenario below, modeled daily revenue after pool fees is $8.92 under PPS+ or $9.10 under PPLNS expected value. At $0.06/kWh, that leaves approximately $3.86 or $4.05 per day after electricity, respectively, before other costs.

These are hypothetical scenario results, not current profitability quotes. Prepared on October 14, 2026, this worksheet uses explicitly assumed difficulty, transaction-fee, and BTC-price inputs. Its purpose is a single-model, recalculable comparison of power costs and ViaBTC's PPS+ and PPLNS fee structures.

Confirm the exact model

Bitmain markets the S21 Pro under more than one power/hashrate configuration, and mixing specifications across variants is a common source of calculation error. This article uses only the 234 TH/s configuration, with a manufacturer-stated typical wall power of 3,510 W and typical efficiency of 15 J/TH, measured at 25°C inlet air temperature. Bitmain's own specification sheet notes that actual hashrate can vary by approximately ±3% and actual wall power or wall efficiency by approximately ±5% across individual units (Bitmain S21 Pro Specification). Before applying any of the figures below to a purchasing or deployment decision, confirm the nameplate on the specific unit, since the 220 TH/s and 245 TH/s variants carry different power draw and will produce different results.

Collect current inputs

A profitability scenario depends on five categories of input, each with a different source and a different degree of volatility.

Hardware specifications—hashrate, wall power, and J/TH—come from the manufacturer for the exact variant; actual operating values depend on the unit and its conditions. Network difficulty determines the expected work required to find a block. Reward inputs consist of the block subsidy and an assumed average transaction fee per block. Market price converts BTC earnings into dollars. Pool-fee schedules require verification against the pool's current published rates.

For this worked example, the inputs below are scenario assumptions, not a verified historical or live market snapshot:

For a fresh calculation, a source such as the Mempool mining dashboard can help collect network inputs. Record the collection time and time zone. If using a trailing 144-block fee average, identify those blocks rather than treating that window as exactly one calendar day. Record the BTC/USD price source separately.

Estimated network hashrate and difficulty are related but distinct. Difficulty is the protocol-adjusted value that targets a 10-minute average block interval; network hashrate is estimated from recent block timing. This worksheet uses difficulty directly, so a separate network-hashrate estimate is not required for its revenue calculation. Refresh the time-sensitive inputs before using the model for a deployment decision.

Model power and pool fees

The electricity-cost side of the model is straightforward. Daily energy consumption is wall power divided by 1,000, multiplied by 24 hours:

3.510 kW × 24 hours = 84.24 kWh/day

Daily electricity cost is then 84.24 multiplied by the applicable rate in dollars per kWh. This is an electricity-only figure; it excludes hosting fees, cooling infrastructure beyond the miner's own draw, repairs, labor, financing, depreciation, and taxes.

The revenue side uses a difficulty-based expected-value model. With hashrate H in hashes per second and difficulty D expressed as its full numeric value:

Expected block-equivalent output/day ≈ H × 86,400 ÷ (D × 2^32)

Here, 234 TH/s is 234 × 10^12 H/s, and 132.72 T difficulty is 132.72 × 10^12. The formula estimates the miner's theoretical daily output at constant difficulty; it does not mean that an individual miner will find a block each day. ViaBTC's PPS subsidy calculation is likewise based on submitted work and current difficulty (ViaBTC: How are profits calculated?).

Apply this expected output separately to the subsidy and transaction-fee assumptions:

• Expected subsidy BTC/day ≈ [234 × 10^12 × 86,400 ÷ (132.72 × 10^12 × 2^32)] × 3.125 = 0.000110837 BTC.
• Expected transaction-fee BTC/day ≈ [234 × 10^12 × 86,400 ÷ (132.72 × 10^12 × 2^32)] × 0.0173 = 0.000000614 BTC.
• Total pre-pool-fee expected BTC/day ≈ 0.000111450 BTC, equivalent to $9.289 at $83,343/BTC.

Calculations retain unrounded values until the displayed result. The transaction-fee estimate assumes that the selected average is representative of the pool's future blocks; actual fee income can differ.

ViaBTC's published PPS+ schedule applies a 4% fee to the PPS-settled block-subsidy component and a 2% fee to the transaction-fee component, which is distributed under PPLNS rules. Its PPLNS schedule applies a single 2% fee to the combined subsidy-plus-fees reward. These published rates were checked on October 14, 2026 (ViaBTC fee schedule). Applying the rates separately gives:

The PPS+ result should not be read as a flat 6% deduction. Because transaction fees are a small share of total reward in this scenario—0.0173 BTC versus a 3.125 BTC subsidy—the effective blended deduction lands just under 4%.

The PPLNS row is an expected-value estimate only: earnings depend on blocks the pool actually finds and the miner's eligible shares. Short-term results can be above or below this figure, and a lower listed fee does not guarantee a higher realized payout over any given day. The transaction-fee portion of PPS+ also varies because it is distributed under PPLNS rules (ViaBTC: Choosing PPS+ or PPLNS).

Stress-test operating margin

Electricity price is usually the largest controllable variable in a mining operation's recurring cost, so the next step is to hold the revenue model fixed and vary only the electricity rate. The table below assumes continuous (100%) operating time and no downtime or rejected-share adjustment; it is a simplified scenario, not an operating guarantee.

These are operating margins after electricity only; they exclude hardware purchase cost, depreciation, financing, hosting fees, site overhead, maintenance, curtailment, and taxes. On an electricity-only basis, the approximate break-even rates under this scenario's assumptions are $0.1059/kWh under PPS+ and $0.1081/kWh under PPLNS expected value:

Electricity-only break-even rate = daily revenue after pool fees ÷ daily kWh

The maximum electricity rate an operator can afford while covering all costs will typically be lower once hosting and other costs are included, since those costs further reduce the margin shown above.

Because the margin is a small residual between two larger numbers—expected revenue and electricity cost—a change of a few cents per kWh, a shift in BTC price, or a change in difficulty can move the result from positive to negative. BTC price changes the dollar value of earnings; it does not, by itself, change the modeled BTC output. Readers using this framework for an actual deployment should substitute their own confirmed electricity rate, current difficulty, transaction-fee assumption, and BTC price rather than treating the figures above as fixed.

Check actual credited rewards

The expected-value model above describes theoretical mining output; it is not the same as what a pool account will show. Four distinct data points should be checked separately rather than assumed to move together:

• Local or device hashrate reported by the miner's own firmware reflects what the hardware is doing at the board level.
• Pool-estimated hashrate is calculated by the pool from recently submitted shares and can diverge from device hashrate due to normal estimation variance, network latency, rejected shares, or partial downtime.
• Accepted and rejected shares indicate how much submitted work qualifies for pool earnings; rejected shares do not earn rewards even when device hashrate appears normal.
• Credited mining rewards are the BTC attributed to the account under the selected payment method. Compare these rewards with the model over the same accounting period.

Keep withdrawals and other transfers separate from this earnings comparison. A transfer can include balances accumulated across multiple days, so its amount is not necessarily the mining income earned on the transfer date.

In a ViaBTC account, review the relevant coin's hashrate, shares, and earnings records. ViaBTC's Profit Detail statistics use UTC+8, so align the model's comparison period accordingly (ViaBTC: How are profits calculated?). Compare BTC amounts first; if converting both to dollars, use the same BTC/USD reference to avoid mistaking price differences for mining-performance differences.

Review a period long enough to account for normal variance, since PPLNS in particular depends on which blocks the pool finds. A single day's discrepancy against the model does not necessarily indicate a hardware or account problem. A sustained divergence is a reasonable trigger to check the model's difficulty and fee assumptions alongside share-rejection rates, reported hashrate, operating time, and payment-method settings.

FAQ

How does a lower J/TH rating affect electricity costs?

At the same hashrate, a lower J/TH rating means less power is needed. J/TH is useful for comparing electrical efficiency, but electricity charges depend on actual energy consumption in kWh. This scenario uses the manufacturer's typical wall-power rating of 3,510 W for the 234 TH/s S21 Pro, equivalent to 84.24 kWh over 24 hours. It is not a measurement of a specific deployed unit; use measured consumption when available.

Why doesn't PPS+ simply charge a combined 6% fee (4% + 2%)?

Because the two rates apply to two separate components of the block reward—4% on the PPS-settled block-subsidy portion and 2% on the transaction-fee portion distributed under PPLNS rules—rather than being added together as a single rate on the whole reward.

Is the PPLNS expected-value figure a guaranteed daily payout?

No. It is a modeled average based on the stated difficulty and reward assumptions. Actual PPLNS earnings depend on the blocks the pool finds and the miner's eligible shares, and can be higher or lower than the expected value on any given day.

How often should the inputs in this scenario be refreshed?

Refresh the time-sensitive inputs before each recalculation. Record the BTC price and its timestamp, the difficulty and corresponding block height, and the transaction-fee averaging window. Also confirm the applicable pool rates, electricity tariff, and actual operating conditions rather than reusing the illustrative assumptions as current figures.

References

• Bitmain, S21 Pro Specification
• ViaBTC, Fee Schedule
• ViaBTC Support, How are profits calculated?
• ViaBTC Support, How to Choose the Optimal Payment Method: PPS+ or PPLNS
• Bitcoin Developer Guide, Mining
• Mempool, Mining Dashboard