Net Dollar Retention Calculator
Net dollar retention (NDR), also called net revenue retention, is the single most-watched health metric for subscription businesses. It measures how much recurring revenue you keep and grow from the customers you already had, counting expansion, contraction, and churn, but deliberately excluding any new customers. Enter your starting recurring revenue and the period's expansion, contraction, and churn in dollars. This calculator returns NDR and gross dollar retention as percentages, so you can separate upsell strength from pure retention.
Net dollar retention formula
Ending base = start + expansion - contraction - churn
NDR (%) = (ending base / start) * 100
Gross dollar retention (%) = ((start - contraction - churn) / start) * 100
NDR includes expansion and can exceed 100%. Gross retention excludes expansion, so it can never exceed 100% and measures pure retention.
Reading retention metrics
- NDR above 100% means the existing base grew despite losses, a strong product-value signal.
- Never include new-customer revenue; NDR measures only the starting base.
- Use the same period and revenue definition (MRR or ARR) for every input.
- Gross retention isolates churn and contraction without the cushion of upsell.
- U.S. SEC filings from public subscription companies disclose comparable retention figures.
Net dollar retention: frequently asked questions
What is net dollar retention?
Net dollar retention (NDR), also called net revenue retention (NRR), measures recurring revenue retained from existing customers over a period, including expansion, contraction, and churn, but excluding new-customer revenue. It is expressed as a percentage of the starting recurring revenue.
How is net dollar retention calculated?
Take starting recurring revenue, add expansion, subtract contraction and churn, then divide by starting recurring revenue and multiply by 100. New-customer revenue is never included because NDR measures only the existing base.
What does NDR above 100 percent mean?
An NDR above 100% means the existing customer base grew in revenue even after losses, because expansion outweighed contraction and churn. This is a strong signal of product value and is highly prized in subscription businesses.
How is gross retention different from net retention?
Gross dollar retention excludes expansion: it is starting revenue minus contraction and churn, over starting revenue. It can never exceed 100% and shows pure retention without the offsetting effect of upsell.
Why exclude new customers from NDR?
NDR isolates how well you keep and grow your existing base. Mixing in new-customer revenue would mask churn behind acquisition. Keeping them separate lets you judge retention and acquisition independently.
Official sources
- U.S. Securities and Exchange Commission: EDGAR company filings (retention disclosures).
- U.S. Securities and Exchange Commission: Guidance on Management's Discussion and Analysis.
Reviewed by the CalculatorHub team, edited by James Graham, 16 June 2026. See our methodology.