A Ruby on Rails Engine which provides a double entry accounting system for your application
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The Plutus plugin is a Ruby on Rails Engine which provides a double entry accounting system for your application.


  • Ruby versions: MRI 1.9.3 - 2.2, Rubinius 2.2, JRuby 1.7+
  • Rails versions: ~> 4.0

For earlier versions, and upgrading, please see the section titled Previous Versions


  • Add the gem to your Gemfile gem "plutus"

  • generate migration files rails g plutus

  • run migrations rake db:migrate


The plutus plugin provides a complete double entry accounting system for use in any Ruby on Rails application. The plugin follows general Double Entry Bookkeeping practices. All calculations are done using BigDecimal in order to prevent floating point rounding errors. The plugin requires a decimal type on your database as well.

Plutus consists of tables that maintain your accounts, entries and debits and credits. Each entry can have many debits and credits. The entry table, which records your business transactions is, essentially, your accounting Journal.

Posting to a Ledger can be considered to happen automatically, since Accounts have the reverse has_many relationship to either its credit or debit entries.


The Account class represents accounts in the system. The Account table uses single table inheritance to store information on each type of account (Asset, Liability, Equity, Revenue, Expense). Each account must be sub-classed as one of the following types:

Asset       | Debit             | Resources owned by the Business Entity
Liability   | Credit            | Debts owed to outsiders
Equity      | Credit            | Owners rights to the Assets
Revenue     | Credit            | Increases in owners equity
Expense     | Debit             | Assets or services consumed in the generation of revenue

Your Book of Accounts needs to be created prior to recording any entries. The simplest method is to have a number of create methods in your db/seeds.rb file like so:

Plutus::Asset.create(:name => "Accounts Receivable")
Plutus::Asset.create(:name => "Cash")
Plutus::Revenue.create(:name => "Sales Revenue")
Plutus::Liability.create(:name => "Unearned Revenue")
Plutus::Liability.create(:name => "Sales Tax Payable")

Then simply run rake db:seed

Each account can also be marked as a "Contra Account". A contra account will have its normal balance swapped. For example, to remove equity, a "Drawing" account may be created as a contra equity account as follows:

Plutus::Equity.create(:name => "Drawing", :contra => true)

At all times the balance of all accounts should conform to the Accounting Equation

Assets = Liabilities + Owner's Equity

Every account object has a has_many association of credit and debit entries, which means that each account object also acts as its own Ledger, and exposes a method to calculate the balance of the account.

See the Plutus::Account, Plutus::Entry, and Plutus::Amount classes for more information.


Recording an Entry

Let's assume we're accounting on an Accrual basis. We've just taken a customer's order for some widgets, which we've also billed him for. At this point we've actually added a liability to the company until we deliver the goods. To record this entry we'd need two accounts:

>> Plutus::Asset.create(:name => "Cash")
>> Plutus::Liability.create(:name => "Unearned Revenue")

Next we'll build the entry we want to record. Plutus uses ActiveRecord conventions to build the transaction and its associated amounts.

entry = Plutus::Entry.new(
                :description => "Order placed for widgets",
                :date => Date.yesterday,
                :debits => [
                  {:account_name => "Cash", :amount => 100.00}],
                :credits => [
                  {:account_name => "Unearned Revenue", :amount => 100.00}])

Entries must specify a description, as well as at least one credit and debit amount. Specifying the date is optional; by default, the current date will be assigned to the entry before the record is saved. debits and credits must specify an array of hashes, with an amount value as well as an account, either by providing a Plutus::Account to account or by passing in an account_name string.

Finally, save the entry.

>> entry.save

If there are any issues with your credit and debit amounts, the save will fail and return false. You can inspect the errors via entry.errors. Because we are doing double-entry accounting, the sum total of your credit and debit amounts must always cancel out to keep the accounts in balance.

Recording an Entry with multiple accounts

Often times a single entry requires more than one type of account. A classic example would be a entry in which a tax is charged. We'll assume that we have not yet received payment for the order, so we'll need an "Accounts Receivable" Asset:

>> Plutus::Asset.create(:name => "Accounts Receivable")
>> Plutus::Revenue.create(:name => "Sales Revenue")
>> Plutus::Liability.create(:name => "Sales Tax Payable")

And here's the entry:

entry = Plutus::Entry.build(
                :description => "Sold some widgets",
                :debits => [
                  {:account_name => "Accounts Receivable", :amount => 50}],
                :credits => [
                  {:account_name => "Sales Revenue", :amount => 45},
                  {:account_name => "Sales Tax Payable", :amount => 5}])

Associating Documents

Although Plutus does not provide a mechanism for generating invoices or orders, it is possible to associate any such commercial document with a given entry.

Suppose we pull up our latest invoice in order to generate a entry for plutus (we'll assume you already have an Invoice model):

>> invoice = Invoice.last

Let's assume we're using the same entry from the last example

entry = Plutus::Entry.new(
                :description => "Sold some widgets",
                :commercial_document => invoice,
                :debits => [
                  {:account_name => "Accounts Receivable", :amount => invoice.total_amount}],
                :credits => [
                  {:account_name => "Sales Revenue", :amount => invoice.sales_amount},
                  {:account_name => "Sales Tax Payable", :amount => invoice.tax_amount}])

The commercial document attribute on the entry is a polymorphic association allowing you to associate any record from your models with a entry (i.e. Bills, Invoices, Receipts, Returns, etc.)

Checking the Balance of an Individual Account

Each account can report on its own balance. This number should normally be positive. If the number is negative, you may have a problem.

>> cash = Plutus::Asset.find_by_name("Cash")
>> cash.balance
=> #<BigDecimal:103259bb8,'0.2E4',4(12)>

The balance can also be calculated within a specified date range. Dates can be strings in the format of "yyyy-mm-dd" or Ruby Date objects.

>> cash = Plutus::Asset.find_by_name("Cash")
>> cash.balance(:from_date => "2014-01-01", :to_date => Date.today)
=> #<BigDecimal:103259bb8,'0.2E4',4(12)>

Checking the Balance of an Account Type

Each subclass of accounts can report on the total balance of all the accounts of that type. This number should normally be positive. If the number is negative, you may have a problem.

>> Plutus::Asset.balance
=> #<BigDecimal:103259bb8,'0.2E4',4(12)>

Again, a date range can be given

>> Plutus::Asset.balance(:from_date => "2014-01-01", :to_date => Date.today)
=> #<BigDecimal:103259bb8,'0.2E4',4(12)>

Calculating the Trial Balance

The Trial Balance for all accounts on the system can be found through the abstract Account class. This value should be 0 unless there is an error in the system.

>> Plutus::Account.trial_balance
=> #<BigDecimal:1031c0d28,'0.0',4(12)>

Contra Accounts and Complex Entries

For complex entries, you should always ensure that you are balancing your accounts via the Accounting Equation.

Assets = Liabilities + Owner's Equity

For example, let's assume the owner of a business wants to withdraw cash. First we'll assume that we have an asset account for "Cash" which the funds will be drawn from. We'll then need an Equity account to record where the funds are going, however, in this case, we can't simply create a regular Equity account. The "Cash" account must be credited for the decrease in its balance since it's an Asset. Likewise, Equity accounts are typically credited when there is an increase in their balance. Equity is considered an owner's rights to Assets in the business. In this case however, we are not simply increasing the owner's rights to assets within the business; we are actually removing capital from the business altogether. Hence both sides of our accounting equation will see a decrease. In order to accomplish this, we need to create a Contra-Equity account we'll call "Drawings". Since Equity accounts normally have credit balances, a Contra-Equity account will have a debit balance, which is what we need for our entry.

>> Plutus::Equity.create(:name => "Drawing", :contra => true)
>> Plutus::Asset.create(:name => "Cash")

We would then create the following entry:

entry = Plutus::Entry.new(
                :description => "Owner withdrawing cash",
                :debits => [
                  {:account_name => "Drawing", :amount => 1000}],
                :credits => [
                  {:account_name => "Cash", :amount => 1000}])

To make the example clearer, imagine instead that the owner decides to invest his money into the business in exchange for some type of equity security. In this case we might have the following accounts:

>> Plutus::Equity.create(:name => "Common Stock")
>> Plutus::Asset.create(:name => "Cash")

And out entry would be:

entry = Plutus::Entry.new(
                :description => "Owner investing cash",
                :debits => [
                  {:account_name => "Cash", :amount => 1000}],
                :credits => [
                  {:account_name => "Common Stock", :amount => 1000}])

In this case, we've increase our cash Asset, and simultaneously increased the other side of our accounting equation in Equity, keeping everything balanced.

Money & Currency Support

Plutus aims to be agnostic about the values used for amounts. All fields are maintained as BigDecimal values, with :precision => 20, :scale => 10, which means that any currency can be safely stored in the tables.

Plutus is also compatible with the Money gem. With Money versions greater than 6.0, the money.amount will returns a BigDecimal which you can use with plutus as follows:

entry = Plutus::Entry.build(
                :description => "Order placed for widgets",
                :debits => [
                  {:account_name => "Cash", :amount => money.amount}],
                :credits => [
                  {:account_name => "Unearned Revenue", :amount => money.amount}])

Multitenancy Support

Plutus supports multitenant applications. Multitenancy is acheived by associating all Accounts under Plutus::Account with a "Tenant" object (typically some model in your Rails application). To add multi-tenancy support to Plutus, you must do the following:

  • Generate the migration which will add tenant_id to the plutus accounts table
bundle exec rails g plutus:tenancy
  • Run the migration
rake db:migrate
  • Add an initializer to your Rails application, i.e. config/initializers/plutus.rb
Plutus.config do |config|
  config.enable_tenancy = true
  config.tenant_class = 'Tenant'

NOTE: When building entries, be sure to specify the account directly, rather than use the account_name feature. Otherwise you'll probably end up with the wrong account.

debit_account = Plutus::Acount.where(:name => "Cash", :tenant => my_tenant).last
credit_account = Plutus::Acount.where(:name => "Unearned Revenue", :tenant => my_tenant).last
entry = Plutus::Entry.new(
                :description => "Order placed for widgets",
                :date => Date.yesterday,
                :debits => [
                  {:account => debit_account, :amount => 100.00}],
                :credits => [
                  {:account => credit_account, :amount => 100.00}])

Reporting Views

The Engine provides controllers and views for rendering basic reports, including a Balance Sheet and Income Statement.

These views and controllers are read-only for reporting purposes. It is assumed entry creation will occur within your applications code.

Routing is supplied via an engine mount point. Plutus can be mounted on a subpath in your existing Rails 3 app by adding the following to your routes.rb:

mount Plutus::Engine => "/plutus", :as => "plutus"

NOTE: The Plutus::ApplicationController does not currently support authentication. If you enable routing, the views will be publicly available on your mount point. Authentication can be added by overriding the controller.

Future versions of plutus will allow for customization of authentication.

Previous Versions

For the rails 3 version, you can go here:


For the rails 2 version, you can go here:


  • Gems in RubyGems.org >= 0.5.0 support Rails 3
  • Gems in RubyGems.org >= 0.8.0 support Rails 4
  • Gems in RubyGems.org >= 0.9.0 support Rails ~> 4.1

Upgrading from older versions

As Plutus is still in alpha, there have been some breaking changes with previous versions.

If you are upgrading, please check the Wiki for guides on how to properly upgrade plutus to deal with the changes:

Upgrade Notes


Rspec tests are provided. Run bundle install then rake.

Contributing and Contributors

There's a guide to contributing to Plutus (both code and general help) over in CONTRIBUTING

Many thanks to all our contributors! Check them all at:


Community and where to get help


Plutus is free software, but if you'd like to support development, feel free to send some bitcoins:



Also, if anyone is using Plutus for bitcoin related accounting, I'd love to hear about it! Drop me a line.


  • Better views, including paging
  • Reference for common accounting entries


For a complete reference on Accounting principles, we recommend the following textbook


Copyright (c) 2010-2016 Michael Bulat