Cryptocurrency Carbon Footprint Calculator
Enter the number of transactions and your chosen cryptocurrency to see the energy consumed in kWh and the carbon emitted in kg CO2. The calculator also benchmarks your result against equivalent hours of household electricity, kilometres driven in a petrol car, and how many Visa card swipes carry the same footprint. Results update instantly as you type, and the worked-steps panel shows every formula used.
Formula
Worked example
One Bitcoin transaction uses approximately 845 kWh (e_coin). At a grid intensity of 490 gCO2/kWh: C = 845 x 490 / 1,000 = 414.05 kg CO2. That energy would power an average US home for 845 / 29 x 24 = 699 hours (~29 days).
How cryptocurrency energy consumption is measured
Every blockchain transaction has to be validated by the network before it is confirmed. For Proof-of-Work coins like Bitcoin and Litecoin, miners compete to solve cryptographic puzzles, and that competition burns electricity at scale. The network's total power draw is estimated by comparing miner revenue (block rewards plus fees) with the cost of electricity, then working back to implied hashrate and energy use. Dividing total network energy by the number of confirmed transactions gives an average energy cost per transaction. This metric is useful for comparing blockchains, but it is worth noting that the same mining energy secures the chain whether a block contains 1 transaction or 3,000, so marginal costs for individuals are close to zero. The per-transaction figure is best read as a network-level allocation rather than a causal individual cost.
Proof-of-Stake networks (Ethereum post-Merge, Solana, Cardano) replaced mining with stake-weighted validator selection. Validators spend negligible electricity compared to PoW miners, cutting per-transaction energy by 99.9% or more. The figures in this calculator reflect those differences: Ethereum's 0.0026 kWh and Solana's 0.00051 kWh per transaction are genuine PoS estimates from the Cambridge Centre for Alternative Finance and ethereum.org.
Carbon intensity and why it matters
Not all electricity is equally carbon-intensive. A Bitcoin miner running entirely on Icelandic geothermal power emits close to zero CO2 per kWh, while the same miner on a coal grid could emit 900-1,000 grams per kWh. The default intensity in this calculator (490 gCO2/kWh) is the Digiconomist weighted global average for the Bitcoin network, derived from a survey of known mining facility locations and their regional grid intensities. You can change the carbon intensity field to reflect a specific mining region or to model a greener scenario:
- Iceland or Norway: 0-20 gCO2/kWh (almost entirely renewables)
- US national average: 389 gCO2/kWh (EPA 2023)
- China national grid: 555 gCO2/kWh
- Coal-heavy grid (e.g. Poland, Kazakhstan): 700-900 gCO2/kWh
Proof-of-Work vs. Proof-of-Stake: the key difference
Bitcoin's energy use is structurally different from Ethereum's because of the consensus mechanism. Proof-of-Work (PoW) rewards miners who expend real-world energy to generate cryptographic hashes, and the difficulty adjusts so that blocks are found on average every 10 minutes regardless of how much hashing power joins or leaves. This means total energy spend rises as more miners compete for the same block reward. Proof-of-Stake (PoS) replaces this arms race with a system where validators lock up cryptocurrency as collateral (stake) and are randomly chosen to propose blocks in proportion to their stake. There is no hash race, so energy use is limited to running a server and storing the chain state, roughly equivalent to a standard web server. Ethereum's switch to PoS on 15 September 2022 (known as the Merge) reduced its energy consumption by over 99.9% overnight. The CCRI (Crypto Carbon Ratings Institute) measured Ethereum's annualised consumption at about 2,601 MWh after the Merge, compared to roughly 21,000,000 MWh before it.
How to interpret the comparison benchmarks
This calculator translates energy and carbon into three familiar benchmarks to give context to the raw numbers.
Household electricity hours: The EIA reports that the average US residential customer uses about 29 kWh per day (10,500 kWh per year). Dividing the transaction energy by 29 and multiplying by 24 gives how many hours that energy would power a home. One Bitcoin transaction at 845 kWh is equivalent to roughly 699 hours, or about 29 days of household electricity.
Driving kilometres: A standard petrol car emits approximately 192 gCO2 per kilometre (IPCC average). Dividing the carbon footprint in grams by 192 gives the equivalent driving distance. This benchmark is intuitive for understanding personal transport comparisons.
Visa transactions: Visa publishes that its network uses about 0.89 kWh per 100,000 transactions (2022 CSR report), or roughly 0.00000089 kWh per transaction. Using a slightly more conservative industry estimate of 0.001485 kWh per Visa transaction (often cited for the Visa network including data centres), one Bitcoin transaction equals approximately 569,000 Visa card payments. These figures are meant for scale illustration, not to suggest Visa is a substitute payment mechanism for crypto.
Per-transaction energy and carbon by cryptocurrency
| Coin | Consensus | kWh / tx | kg CO2 / tx | vs. Bitcoin |
|---|---|---|---|---|
| Bitcoin (BTC) | PoW | 845 | 0.4141 | 1x (baseline) |
| Litecoin (LTC) | PoW | 18.5 | 0.00907 | ~45x fewer |
| Dogecoin (DOGE) | PoW | 0.12 | 0.0000588 | ~7,000x fewer |
| XRP | Federated consensus | 0.0079 | 0.0000039 | ~107,000x fewer |
| Cardano (ADA) | PoS | 0.05159 | 0.0000253 | ~164,000x fewer |
| Ethereum (ETH) | PoS | 0.0026 | 0.00000127 | ~325,000x fewer |
| Solana (SOL) | PoS | 0.00051 | 0.00000025 | ~1,660,000x fewer |
Reference figures used in this calculator. Carbon assumes 490 gCO2/kWh (Digiconomist global weighted average). PoW = Proof-of-Work, PoS = Proof-of-Stake.
Frequently asked questions
How much energy does one Bitcoin transaction use?
One Bitcoin transaction uses approximately 845 kWh on average, according to the Digiconomist Bitcoin Energy Consumption Index (2025 estimate). That is enough electricity to run a typical US home for about 29 days. The figure fluctuates with network hashrate and transaction volume, so live indices like Digiconomist update it periodically.
Is Ethereum still bad for the environment after the Merge?
No, not nearly as bad as it used to be. Before September 2022, Ethereum used Proof-of-Work and consumed around 21 TWh per year. After switching to Proof-of-Stake (the Merge), annual consumption fell to approximately 2,601 MWh, a reduction of more than 99.9%. A single Ethereum transaction now uses about 0.0026 kWh, comparable to a few seconds of laptop use.
Which cryptocurrency has the lowest carbon footprint?
Among popular coins, Solana and Ethereum (post-Merge) have the lowest per-transaction footprints, at roughly 0.00051 kWh and 0.0026 kWh respectively. XRP, Cardano, and Algorand are also low-energy because they use non-mining consensus mechanisms. Bitcoin and Litecoin remain the most energy-intensive because they use Proof-of-Work mining.
What is the carbon footprint of one Bitcoin transaction?
At a grid carbon intensity of 490 gCO2/kWh (the Digiconomist global weighted average for Bitcoin miners), one Bitcoin transaction emits roughly 414 kg CO2. That is comparable to driving a petrol car approximately 2,157 km, or flying from London to Dubai as a single passenger.
Why can cryptocurrency footprint figures vary so much between sources?
Three factors cause the wide variation: methodology (economic top-down vs. hardware bottom-up models), the assumed carbon intensity of the electricity mix (coal vs. renewables vs. a weighted average), and whether the calculation uses current or historical network data. This calculator uses the Digiconomist economic model and a 490 gCO2/kWh default, but you can enter any intensity figure to model a different scenario.
Does more blockchain usage make the footprint worse?
For Proof-of-Work chains like Bitcoin, total network energy is driven mainly by miner revenue (block rewards and fees), not by the number of transactions. More transactions in a block do not proportionally increase energy use because difficulty adjusts to maintain a fixed block rate. For Proof-of-Stake chains, energy is largely fixed regardless of throughput. Per-transaction figures are allocations of network-level energy, not causal per-use costs.
Can I use a lower carbon intensity if my crypto exchange uses renewables?
Yes. The carbon intensity input lets you override the global default. If your transaction is on a network that publicly reports a higher renewable share, or you have offset your share, you can enter a lower gCO2/kWh value. For example, 20 gCO2/kWh reflects an almost fully renewable grid like Iceland. The carbon output will update immediately.