🪙 Dime

Calculate your cryptoasset taxes in the UK

About

Dime is a free and open-source command-line tool written in PHP to calculate your cryptoasset taxes in the UK.

It takes a spreadsheet of transactions as input and returns the corresponding tax figures per tax year.

Dime is primarily intended for people already familiar with the UK's cryptoassets tax rules looking for a privacy-preserving way to complete their tax return.

Dime is a project by Yannick Chenot that is also the object of a blog series.

Disclaimer

This program is Copyright (C) 2022 by Yannick Chenot.

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should seek the advice of a professional accountant before using this program.

Table of contents

• Installation
  • Standalone application 🧪
  • Composer
  • PHAR (Linux / Unix / macOS)
  • Docker
• Usage
• Spreadsheet format
  • Date
  • Operation
  • Market value
  • Sent asset
  • Received asset
  • Fee
  • Income
  • Summary
  • Special cases
• How it works
• Maintenance
  • Upgrade
  • Delete
• Issue reporting
• Contributing

Installation

Standalone application 🧪

[!NOTE] This is an experimental feature. Please open an issue if the application doesn't behave as expected.

Download the binary for your operating system:

You can use the application straight away:

Or you may want to move it to a directory that is in your system's PATH:

You can now run dime from anywhere instead of ./dime-<YOUR-OS>.

Composer

[!IMPORTANT] Requires Composer as well as PHP 8.2 and the BCMath extension.

You can instal Dime via Composer:

Once the script is done, you should be able to run dime from anywhere to use the application.

If not, make sure the ~/.composer/vendor/bin directory is in your system's PATH.

PHAR (Linux / Unix / macOS)

[!IMPORTANT] Requires PHP 8.2 and the BCMath extension.

Download the PHAR archive from the latest release.

You can use the application straight away:

Or you may want to move it to a directory that is in your system's PATH:

You can now run dime from anywhere instead of php dime.

Docker

[!IMPORTANT] Requires Docker and sh or Bash.

Download this shell script and use it straight away:

It will download Dime's Docker image and pass on commands to it.

You may also want to move the script to a directory that is in your system's PATH:

You can now run dime from anywhere.

Usage

Display Dime's menu by calling the executable without arguments:

Here is a brief description of the main commands.

Processing transactions

Pass your transaction spreadsheet to the process command:

It will validate and process each transaction and display the corresponding tax figures or report any errors.

[!TIP] You will need to run this command every time you update the spreadsheet.

See the Spreadsheet format section to learn how to report your transactions.

Reviewing a tax year

Once your transaction spreadsheet has been processed you can review the corresponding tax figures whenever you like without having to run the process command again.

To list the available tax years and pick one to review:

To review a specific tax year:

Calling the review command without specifying a tax year will also display your current fiat balance (the difference between the fiat amount you put in and the fiat amount you took out).

Spreadsheet format

Here is a sample CSV file you can use as a starting point. It is recommended to read this entire section to ensure proper reporting, however.

Your spreadsheet must contain at least the following columns:

Column names are not case-sensitive and columns can be in any order. Extra columns will be ignored by the program.

Date

The expected date format is DD/MM/YYYY (e.g. 21/10/2015).

You can also specify the time of the transaction, although Dime doesn't need it.

Operation

Accepted values: receive, send, swap, and transfer.

Each operation requires different columns to have values (see detail below). You can also use the sample CSV file as a guide.

Receive

This operation is for transactions where you receive a cryptoasset in exchange for nothing. This happens when someone gifts you some crypto, for instance, or when you get or claim an airdrop.

receive transactions require values for the Market value, Received asset, and Received quantity columns.

Send

This operation is for transactions where you send a cryptoasset and do not receive another cryptoasset or some fiat currency in exchange. This happens when you gift someone some crypto, for instance, or when you pay for a product or service using a cryptoasset.

send transactions require values for the Market value, Sent asset, and Sent quantity columns.

Swap

This operation is for transactions where you exchange a cryptoasset (or some fiat currency) for another cryptoasset (or some fiat currency). This happens when you buy some crypto off an exchange, for instance, or when you sell some crypto, or you exchange a cryptoasset for another one.

In any case, at least one side of the transaction must be a cryptoasset.

swap transactions require values for the Market value, Received asset, Received quantity, Sent asset, and Sent quantity columns.

Transfer

This operation is for transactions where you transfer a cryptoasset from and to a wallet that you control. This happens when you withdraw some crypto from an exchange and send it to your hardware wallet, for instance.

transfer transactions require values for the Sent asset and Sent quantity columns.

Market value

The market value of a transaction is its value expressed in pound sterling at the time of the transaction.

The market value is at the centre of Dime's calculation rules so it is crucial to report it correctly.

Rules

When the transaction includes a sent asset (and is not a transfer – transfers don't need a market value), you must use the sent asset's market value as the transaction's market value, based on the reported sent quantity (see Sent quantity section below to learn how to report it correctly).

[!IMPORTANT] Be particularly vigilant when selling an asset for some fiat currency. It is tempting to use the received fiat amount as the market value, but if a fee was taken, the actual market value is the received amount plus the fee's market value.

When the transaction does not include a sent asset (i.e. receive transactions), the transaction's market value is the received asset's market value.

How to find the market value

There are several ways to figure out a transaction's market value.

Keeping in mind that when a transaction includes a sent asset, its market value takes precedence:

• If the sent asset is a fiat amount, use that as the market value;
• If performing a transaction on an exchange, use the exchange's rate for the asset at the time of the transaction;
• If using a decentralised protocol, use the value reported by the corresponding blockchain's explorer (see the value between brackets in the Tokens Transferred section here, for instance);
• If none of the above applies, look up the asset on price-tracking websites such as CoinMarketCap or CoinGecko.

[!TIP] If any of the above amounts are expressed in a foreign currency, use HMRC's exchange rates to convert them to pound sterling.

Sometimes, while the transaction includes a sent asset, its price isn't tracked anywhere. In that case, use the received asset's market value plus the fee's market value, if you paid for that fee.

In some cases, none of the transaction's asset prices are tracked anywhere. When that happens, you are supposed to figure out the assets' fair market value, although there is no clear guidance on how to do that.

Sent asset

A sent asset must be specified for send, swap, and transfer transactions.

Here is the detail of each related column.

Sent asset

This is the sent asset's symbol, or ticker (e.g. BTC for Bitcoin or GBP for pound sterling).

If the asset is an NFT, you can use any string value you like, so long as it is unique in your spreadsheet. I usually go for the collection's ID followed by the item's number (e.g. this CryptoPunk would be ID 0xb47e3cd837ddf8e4c57f05d70ab865de6e193bbb/1008).

Sent quantity

The quantity sent. For NFTs, that would be 1.

Be as precise as possible and report all available decimal places.

[!IMPORTANT] When the sent asset and the fee's currency are the same (e.g. GBP in both cases), and the fee's quantity was deducted from the sent quantity, the sent quantity must exclude the fee's quantity.

• Example #1: If you send £50 to an exchange and spend it all in a transaction that incurs a £0.50 fee, the sent quantity is 49.5.
• Example #2: If you swap 1 bitcoin for 10 ethers on an exchange and the transaction incurs a BTC 0.01 fee, the sent quantity is 0.99.

Sent asset is non-fungible

Whether the sent asset is an NFT. This is a boolean value that can be any of true, yes, y, and 1. If your spreadsheet software allows you to insert checkboxes in your cells, use that.

Received asset

A received asset must be specified for receive and swap transactions.

Here is the detail of each related column.

Received asset

This is the received asset's symbol, or ticker (e.g. BTC for Bitcoin or GBP for pound sterling).

If the asset is an NFT, you can use any string value you like, so long as it is unique in your spreadsheet. I usually go for the collection's ID followed by the item's number (e.g. this CryptoPunk would be ID 0xb47e3cd837ddf8e4c57f05d70ab865de6e193bbb/1008).

Received quantity

The quantity received. For NFTs, that would be 1.

Be as precise as possible and report all available decimal places.

Received asset is non-fungible

Whether the received asset is an NFT. This is a boolean value that can be any of true, yes, y, and 1. If your spreadsheet software allows you to insert checkboxes in your cells, use that.

Fee

While the related values are optional, most transactions will incur a fee.

Different values must be used depending on the context:

• If the transaction is on-chain (e.g. performed through a decentralised protocol), use the blockchain's fee (i.e. as reported by the block explorer);
• If the transaction was conducted on an exchange, use the exchange's fee, even if there is a corresponding on-chain transaction.

The reason for the latter is that exchanges usually estimate how much the fee will be and charge that estimate. This amount is almost always different from the actual fee, but that's the amount you will be charged anyway.

[!TIP] Be sure not to report fees that you didn't pay for. For instance, if you received an airdrop that was sent by the token issuer and the transaction includes a fee, the issuer paid for that fee, not you, so you don't have to report it.

Here is the detail of each fee-related column.

Fee currency

This is the symbol (or ticker) of the asset used to pay for the fee (e.g. BTC for Bitcoin or GBP for pound sterling).

Fee quantity

The quantity used for the fee.

Be as precise as possible and report all available decimal places.

Fee market value

The market value of a fee is its value expressed in pound sterling at the time of the transaction. See Market value for details.

Income

Some transactions are considered income by HMRC. A typical example is an airdrop received because of some past activity.

For instance, if you had purchased an ENS domain before November 2021, you would have received some ENS tokens as part of their airdrop. This was a reward based on something done in the past, which is considered income by HMRC.

The Income column is a boolean value that can be any of true, yes, y, and 1. If your spreadsheet software allows you to insert checkboxes in your cells, use that.

Summary

Here is a summary of the important rules:

• Always use the sent asset's market value when available, even if the received asset is a fiat amount;
• Transfers don't need a market value;
• The sent quantity must exclude the fee's quantity when the sent asset and the fee's currency are the same;
• The sent asset's market value must be based on the reported sent quantity;
• In receive transactions, the market value is the received asset's market value;
• Use HMRC's exchange rates to convert foreign currency amounts to pound sterling.

If you got this far you must have realised by now that reporting transactions is a bit of work. Dime grants you more control over your reporting but the trade-off is that it is your responsibility to do it well.

In other words, the returned tax figures are only as good as the spreadsheet's accuracy.

Special cases

Here is a list of edge cases that need to be reported in a certain way to be correctly processed.

Minting an NFT out of several other NFTs

How it works

Dime processes the transactions contained in your spreadsheet and saves them in a local SQLite database along with the tax figures that it computes.

The database file is located within your user directory's .dime folder:

Everything is processed locally – your transactions never leave your computer.

A technical description of the architecture is available here.

Maintenance

Upgrading and deleting Dime depends on how you installed it in the first place.

Upgrade

If you have installed Dime via Composer, this is how to upgrade to a minor version (e.g. v1.1):

To a major version (e.g. v2.0):

If you have installed Dime by downloading the PHAR archive:

If you have installed Dime via Docker:

Delete

If you have installed Dime via Composer:

If you have installed Dime by downloading the PHAR archive, you need to manually delete it from its location, e.g.:

If you have installed Dime via Docker:

In all cases, you also need to delete the .dime folder (unless you want to keep the database):

Issue reporting

I don't take feature requests at this stage (although I will look at pull requests – see Contributing below), but I will try and address bugs as well as any issue related to reported figures.

If Dime seemingly crashes for no reason or returns numbers that appear to be wrong, please file an issue here using the relevant template.

Also, feel free to open a discussion for anything else related to the program (e.g. tax rules, how to report something in the spreadsheet, etc.). I cannot guarantee that I will personally reply, but someone else might.

Contributing

I don't take feature requests at this stage but pull requests are welcome. See CONTRIBUTING for details.

Also, make sure to open a discussion before you take on any significant work to avoid disappointment.