Proper books, built from public data.
Carnet reads back your wallets’ history on the blockchains, fills in the gaps from your Coinbase statements and works out what wallet apps don’t show you: cost basis, capital gains, the real yield of your staking.
What everything is worth, in euros, at a glance.
Total value, cost basis, unrealised and realised gains, staking income and network fees. The chart sets your portfolio’s value against what it cost you, over 3 months, 1 year, 3 years or since day one.
- What it’s all worth, in euros, and where it sits: Ledger or Coinbase.
- Its value, against what it cost you.
- Weighted average cost (WAC) or FIFO, whenever you like.
- Staking income, counted separately.
- Hide the amounts in one click.
The dashboard. Made-up demo data.
- WAC and FIFO
- Both methods are always calculated, and you switch between them in one click.
- Breakdown
- By crypto, and by where it’s held (Ledger or Coinbase).
- Yearly summary
- Acquisitions, disposals, realised gains, staking income and fees, year by year.
- Hide amounts
- One click, for when you open Carnet with other people around.
Your Ledger accounts, read-only.
Add an account by pasting its public identifier. Carnet finds all its addresses, its balances and its full history, then checks that the movements really do add up to the balance the blockchain shows.
- An account tracked through its extended public key. The Ledger itself stays unplugged.
Wallets. Made-up demo data.
| Blockchain | What you paste | What gets tracked |
|---|---|---|
| Bitcoin | The “Advanced” JSON block from Ledger Wallet, an xpub/ypub/zpub or an address | BTC, all accounts |
| Ethereum | A 0x… address | ETH, ERC-20 tokens, stETH, rETH, validators |
| Solana | The account address | SOL, SPL tokens, stake accounts |
| Cardano | An addr1… or stake1… address | ADA, delegation; native tokens (quantities only, with no euro price) |
| XRP Ledger | An r… address | XRP, reserve, issued tokens (RLUSD…) |
| Litecoin | As for Bitcoin: the “Advanced” JSON block, an xpub/Ltub/Mtub or an address | LTC |
| Dogecoin | As for Bitcoin: the “Advanced” JSON block, a dgub or an address | DOGE |
| Bitcoin Cash | As for Bitcoin: the “Advanced” JSON block, an xpub or an address | BCH |
| Zcash | As for Bitcoin: the “Advanced” JSON block, an xpub or a t1… address | ZEC, transparent part only |
| Arbitrum One, Avalanche C-Chain, BNB Smart Chain, Cronos, HyperEVM | A 0x… address | The network’s coin (ETH, AVAX, BNB, CRO, HYPE) and tokens from the built-in lists |
Public addresses from other wallets work the same way. NFTs, Zcash shielded funds, BNB Smart Chain staking and the history of layer-2 networks other than Arbitrum One (Base, Optimism…) aren’t tracked.
Your Coinbase history, linked to your Ledger.
The blockchain knows when your crypto reached your Ledger, not how much you paid for it. Your Coinbase statements do. Carnet links each send from Coinbase (or withdrawal from Coinbase Pro) to its arrival on your Ledger, so your crypto keeps its original purchase price.
- A bitcoin purchase, taken from the Coinbase statement along with its price.
Transactions, filtered to one year. Made-up demo data.
- Coinbase
- The “Transaction history” statement as a CSV file, older formats included.
- Coinbase Pro
- Yearly “Account” reports, with orders and fees grouped together. Coinbase only guarantees access to these statements until the end of 2026.
- No duplicates
- Importing a file again, or files that overlap, doesn’t create duplicates.
- You stay in charge
- Filter by account, crypto or type, correct a transaction’s type or value, confirm or reject a match.
- Purchase price unknown?
- Crypto received from elsewhere is valued at the price on the day it arrived and flagged as an estimate; you can enter what you actually paid.
Two ways to count. Carnet keeps both.
WAC (weighted average cost) or first in, first out (FIFO): both are calculated all the time, and you switch from one to the other in a click. Unrealised and realised gains, with network fees counted separately.
| WAC | FIFO | |
|---|---|---|
| Sale proceeds | €6,000.00 | €6,000.00 |
| Cost basis | −€4,000.00 | −€3,000.00 |
| Gain | €2,000.00 | €3,000.00 |
For information only. Carnet doesn’t fill in your tax return.
What your staking really earns.
Carnet spots Solana stake accounts, Cardano delegation, liquid staking tokens (stETH, rETH, JitoSOL…), Ethereum validators and Coinbase staking by itself. Then it measures the yield from the rewards you actually received.
- The real yield over 30 days, 90 days and 12 months.
The Staking page. Made-up demo data.
- Real yield
- Per crypto, over rolling 30 days, 90 days and 12 months, measured against the quantity actually staked.
- Rewards
- By month and by year, in coins or in euros, at today’s price or the price on the day you received them.
- Estimates
- The next 12 months per crypto, and projections over 1 to 10 years, with or without reinvestment, based on what you have staked today.
- Filters
- By crypto and by source: Ledger only (as in Ledger Wallet), Coinbase only, or both.
How projections work, over 1 to 10 years. A diagram, no figures.
An estimate, not a promise: the yield is assumed to stay constant, the price is a guess, and you can adjust both.
Everything else.
- “To review”
- A Coinbase send with no matching arrival, a crypto with no price, a balance that doesn’t add up, a sync that was cut short: each item is explained, alongside the transaction concerned.
- Prices in euros
- Daily price history in dollars, converted at the European Central Bank rate, and current prices refreshed after every sync or import.
- Accounting settings
- Default method (WAC or FIFO), rewards at the day’s price or at zero cost, and a French-rules option: crypto-to-crypto swaps realise no gain, and the cost basis carries over.
- Screen privacy
- Amounts hidden in one click. On a computer, Carnet also asks the system to keep its window out of screenshots and screen sharing (how well that works depends on the tool).
- Encrypted backup
- Export a copy of the vault, still encrypted with your password, to keep somewhere other than your device.
- Your own node
- For each blockchain, you can swap the default public service for your own server (HTTPS, or a .onion address over Tor).
What Carnet doesn’t do (yet).
- No official tax return: Carnet doesn’t apply the formula in article 150 VH bis of the French tax code (Code général des impôts). WAC and FIFO are shown for information only.
- No NFTs, no Zcash shielded funds, no BNB Smart Chain staking, no history on layer-2 networks other than Arbitrum One (Base, Optimism…).
- No exchange other than Coinbase and Coinbase Pro for now.
- Rewards from “compounding” Ethereum validators earned before the first sync can’t be rebuilt from free sources.
- No currency other than the euro: the app (in English or French) counts in euros only.
Carnet is coming soon.
On its way to Mac, Windows, iPhone and Android. No sign-up, and your data stays on your device.