The allowance for bad debts is a reserve against the amount of accounts receivable that customers may not pay. When actual bad debts are recognized, they are charged against this allowance account.
By using an allowance for bad debts, a business can charge off the incremental expected change in bad debts as soon as receivables are recorded. This approach tends to result in the more rapid recognition of bad debts, rather than waiting for specific bad debts to be identified, which may be several months later. The use of an allowance also tends to result in the recognition of a more consistent amount of bad debt expense from period to period.
The allowance for bad debts is also called the allowance for doubtful accounts.