Reading profit estimates, sensitivity, and payback honestly
Every profitability number is a snapshot of assumptions. Learn the anatomy of an estimate, which inputs move the answer most, and why simple payback is a planning ratio — not a promise.
Anatomy of an estimate
Net = (expected coins/day × price) − power cost − pool fee − other costs. Expected coins/day comes from your hashrate share (your hashrate ÷ network hashrate × daily emission) — every term decays or floats: network hashrate grows, price moves, tariffs change. A calculator that shows one net number without its inputs is marketing, not math.
Sensitivity: what moves the answer
Round-number rig: 100 MH/s on a small chain, $0.10/kWh, netting $4.00/day at today's numbers. Nudge one input at a time:
| Input change | Effect on net | Likely? |
|---|---|---|
| Price −20% | $4.00 → $3.10 | Always possible |
| Network hashrate +50% (share −33%) | $4.00 → $2.90 | Normal on growing small chains |
| Tariff $0.10 → $0.15 | $4.00 → $2.80 | Check your bill, not the internet |
| Uptime 100% → 90% | $4.00 → $3.60 | Realistic year-one |
Simple payback, and its limits
Simple payback = upfront cost ÷ operating NET per period (never gross revenue). $3,000 ÷ $10/day = 300 days; at $5/day it is 600 days; at $0/day it is never. It ignores time-value of money, difficulty growth, repairs, and hardware resale — treat it as a comparison ratio between scenarios, not a date you can book.
- Include ALL upfront costs (delivery, electrical work, racks) in the numerator.
- Use net margin per day in matching currency — gross revenue flatters by 2–3×.
- If the margin is zero or negative, payback is infinite; no spreadsheet formatting fixes physics.
See it live on pow.family
The Tools section computes all of this from live coin data — price, network hashrate, and pool fees pulled from the same harvester that feeds the site, with every assumption visible in the input panel.