Quick guide
How to use this calculator
- Enter only the business amounts, rates, counts, or operating assumptions named by the fields.
- Keep currencies, reporting periods, quantities, and accounting classifications consistent.
- Review the formula and calculator-specific limitations before using the result in a decision.
Calculation method
Calculation method
Retention = (ending customers − new customers) ÷ starting customers × 100%.
Fixed-decimal arithmetic remains exact through display unless a result is explicitly labelled approximate, such as a square-root inventory quantity.
Worked example
Worked example
Starting with 1,000 customers, ending with 1,050 after adding 150 gives 90% retention.
Retention = (ending customers − new customers) ÷ starting customers × 100%.
Supported inputs
Precision and limits
Visible input limits
Fixed decimals accept up to 30 digits and 12 decimal places and are capped at an absolute value of 1e12 per input. Rates are capped at 1000%; percentage shares and method-specific domains may be narrower.
International scope
No currency, tax jurisdiction, accounting framework, payroll rule, marketplace fee schedule, financing term, or industry benchmark is selected automatically.
Decision boundary
Results are arithmetic scenarios from visitor-entered assumptions, not accounting records, forecasts, valuations, legal interpretations, professional advice, or recommendations.
Calculator-specific assumptions
This is a scenario from visitor-entered values. Keep currencies, periods, accounting classifications, and operating definitions consistent. It is not accounting, tax, legal, investment, or business advice.