noun
A book or register for recording financial transactions or accounts.
毎月の収支を計算簿に記入する。
I record my monthly income and expenses in the account book.
会計簿 is a formal accounting ledger, often used in business contexts, whereas 計算簿 can be used for personal or simpler record-keeping.
Compound of 計算 (calculation) and 簿 (book, register).