Hi, I'm Joven, and I work with Jingle Mining. I often see profitability screenshots compared as if they were fixed facts. They are not. This worksheet is the process I use to check whether two ASIC estimates are actually based on the same assumptions.
1. Lock the exact hardware variantA model name is not enough. Record the advertised hashrate, wall power, efficiency, input voltage, cooling type and firmware mode. Two listings with similar names can have different ratings. If the seller cannot identify the exact variant, stop the comparison there.
2. Separate stable inputs from live inputs- Hardware: Hashrate, wall power, voltage and cooling. These usually come from the manufacturer specification.
- Electricity: Use the all-in $/kWh rate, not only the headline tariff.
- Uptime: Use a realistic percentage after outages and maintenance.
- Network: Save difficulty or hashprice with a timestamp because it changes continuously.
- Pool: Record the fee and payout method.
- Site overhead: Include ventilation, cooling, networking and labor.
- Ownership cost: Include landed price, tax, repair and downtime reserve.
3. Calculate energy cost before looking at revenueDaily energy use = rated kW × 24 × uptime fraction
Daily energy cost = daily energy use × all-in electricity rate
As a worked example, Bitmain rates the air-cooled Antminer S21 at 200 TH/s and 3,500W. At 95% uptime, the miner-only energy use is:
3.5 kW × 24 × 0.95 = 79.8 kWh/day- At $0.06/kWh: $4.79/day or $143.64 per 30 days
- At $0.10/kWh: $7.98/day or $239.40 per 30 days
- At $0.14/kWh: $11.17/day or $335.16 per 30 days
These figures are energy costs only. They do not include revenue, pool fees, cooling, tax, shipping or repairs.
4. Use three cases instead of one payback number- Downside case: Lower uptime, higher electricity cost and a conservative live revenue assumption.
- Base case: Assumptions supported by current bills and actual site history.
- Upside case: Useful for sensitivity testing, but not as the purchase justification.
Simple payback = landed hardware cost ÷ net daily cash flow.
If net daily cash flow is zero or negative, a positive payback period does not exist under that scenario.
5. Check every estimate at the same timestampWhen two calculators disagree, first align the model variant, power, electricity rate, pool fee, uptime and network timestamp. Comparing one tool's live result with another tool's older screenshot is not a valid test.
Useful checks:
Jingle Mining ASIC comparatorWhatToMineminerstatQuestions I would ask before paying- Is the quoted power measured at the wall or copied from a nominal specification?
- Does the price include shipping, tax, customs and the correct power cord or PDU requirement?
- What uptime has this site actually achieved over the last 30 or 90 days?
- How are repair time, spare parts and failed hashboards treated in the model?
- What date and time were the network and coin-price inputs captured?
I would be interested to see what uptime and repair-reserve assumptions other operators use. Those two inputs often explain more than the headline calculator result.
Disclosure: I work with Jingle Mining. The Jingle Mining link is a first-party comparison tool. Bitmain's official specification and neutral live-data tools are provided so the figures can be checked independently.
