FTB-C000715 / Financial concept

Average daily balance

Average daily balance is the arithmetic average of eligible daily balances over a specified period.

Also known asADB

Intermediate Formula defined 2 linked topicsEvidence-reviewed

Definitions

In plain terms

Add the balance for every included day and divide by the number of included days.

Technical

D30 keeps the sum and day count exact; an average can be fractional in minor units and should not be rounded before the declared interest calculation.

Scope

Eligible balance, daily cutoff, missing days and the related fee/interest method require separate rules.

Formula

ADB = sum(B_d for d=1..N) / N
LaTeX: \operatorname{ADB}=\frac{1}{N}\sum_{d=1}^{N}B_d
SymbolMeaningUnit
B_deligible balance for included day dcurrency units
Nnumber of included days, greater than zerodays

Output unit: currency units, possibly fractional

Examples

  • Synthetic daily balances 10,000 and 12,001 cents have an exact average of 11,000.5 cents.

Common misconceptions

  • The average of transaction rows is not necessarily the average of daily balances.

Concept relationships

Related

Where this concept is used

Evidence and governance

  1. Regulation DD, 12 CFR 1030.2: Definitions Consumer Financial Protection Bureau · official standard

    Supports: preferred label, short definition, variant distinction

    Limits: Not a universal eligible-balance, fee, APY or rounding contract.

  2. D30 glossary teaching-profile scope, Batch 013 The Fintech Builder · internal governed contract

    Supports: technical definition, formula, units

    Limits: No independent regulatory mandate, real-bank dataset, service execution, external witness or production assurance is claimed.

Reviewed by
fintech-builder-batch-013
Last reviewed
2026-10-27
Next review
2027-10-27
Record status
evidence reviewed

This record is evidence-reviewed and readable, but not yet promoted to published — it is served noindex,follow and excluded from the sitemap.

Written by

Fintech engineer building market-data and financial systems, and the author of every article, glossary record, and reference implementation on The Fintech Builder.