larzledger

Exact double-entry accounting in pure Python. Zero dependencies.

A correct ledger: every transaction is balanced debits and credits (rejected if they don't balance), account balances follow real accounting's normal-side rules, and money is exact Decimal — never a float, so the books never drift by a cent.

from larzledger import Ledger

led = Ledger(currency="$")
led.account("cash", "asset")
led.account("revenue", "income")
led.account("rent", "expense")

led.transaction("Sale").debit("cash", "250.00").credit("revenue", "250.00").commit()
led.post("Rent", debit=("rent", "1200.00"), credit=("cash", "1200.00"))

led.balance("cash")                 # Decimal('-950.00')
led.trial_balance()                 # debits == credits, guaranteed
led.accounting_equation_holds()     # True

Why

• Actually double-entry. Debits must equal credits or the transaction is refused — the core invariant that keeps books trustworthy.
• Exact money. Decimal throughout; floats are rejected on purpose. Balances, trial balance, and the accounting equation always reconcile to the cent.
• Real accounting semantics. Asset/expense accounts are debit-normal; liability/equity/income are credit-normal — balances read positive on the right side.
• Money-native, zero-dep. Amounts accept strings, ints, Decimal, or larzmoney Money objects. No dependency, no database — bring your own storage.

Install

pip install larzledger

Usage

led.account(name, "asset"|"liability"|"equity"|"income"|"expense")

# transaction builder (any number of legs; must balance)
led.transaction("desc").debit("a", "10").credit("b", "10").commit()

# convenience for simple entries (amounts can be dicts of account->amount)
led.post("Split", debit={"rent": "50", "cash": "50"}, credit={"revenue": "100"})

# reporting
led.balance("cash")
led.trial_balance()                 # [(name, type, debit, credit), ...]
led.total("asset")                  # sum of an account type
led.statement("cash")               # every posting touching an account
led.accounting_equation_holds()     # assets == liabilities + equity + income - expense
led.format("1234.5")                # "$1,234.50"

Tests

python -m unittest discover -s tests -v   # 17 tests, zero deps

The Larz stack

Part of a family of pure-Python, zero-dependency libraries — money-native (larzmoney, larzpdf), and 30+ more at github.com/larz-scripter.

License

MIT © larz-scripter