What is Net Dollar Retention (NDR)? (Definition + SaaS example)
Net Dollar Retention (NDR) measures the percentage change in revenue from existing customers over a period, accounting for expansion, contraction, and churn. NDR above 100% indicates that revenue growth from upsells and cross-sells exceeds revenue lost from downgrades and cancellations — the clearest signal of a sticky, expanding product.
Formula and Calculation
Net Dollar Retention
NDR = (Starting Revenue + Expansion − Contraction − Churn) ÷ Starting Revenue × 100
NDR is typically measured on a trailing 12-month basis using a specific customer cohort:
Cohort NDR
NDR = Revenue from Same Cohort at End of Period ÷ Revenue from Cohort at Start of Period × 100
Worked SaaS Example
A SaaS company tracks its January 2025 customer cohort (all customers active on Jan 1, 2025):
| Cohort Activity (Jan 2025 → Jan 2026) | MRR Impact |
|---|---|
| Starting MRR (Jan 2025) | $400,000 |
| + Expansion (upgrades, seat additions) | $72,000 |
| − Contraction (downgrades) | −$18,000 |
| − Churn (cancellations) | −$32,000 |
| Ending MRR from cohort (Jan 2026) | $422,000 |
NDR = $422,000 ÷ $400,000 × 100 = 105.5%
The existing customer base grew by 5.5% in dollar value, despite losing some customers entirely.
NDR Breakdown by Segment
| Segment | Starting MRR | Ending MRR | NDR |
|---|---|---|---|
| Enterprise | $250,000 | $295,000 | 118% |
| Mid-market | $100,000 | $98,000 | 98% |
| SMB | $50,000 | $29,000 | 58% |
| Total | $400,000 | $422,000 | 105.5% |
The blended NDR of 105.5% masks significant variation. Enterprise customers expand aggressively (118%), while SMB customers churn heavily (58%). This informs where to focus retention investment.
NDR vs NRR
In most SaaS contexts, NDR and NRR are used interchangeably. The distinction is academic — both answer the same question: is the existing customer base becoming more or less valuable over time?
Why Net Dollar Retention Matters for SaaS
Finance teams use NDR as the most reliable indicator of long-term revenue durability. A company with 115% NDR knows that even with zero new customer acquisition, revenue from existing customers grows 15% annually. This creates a compounding growth engine that reduces dependence on the sales team.
In investor reporting, NDR is prominently featured in S-1 filings, earnings calls, and fundraising decks. It has become the single most cited retention metric in public SaaS because it captures the net effect of all customer revenue dynamics — expansion, contraction, and churn — in one number.
A common mistake is reporting NDR without segmentation. A 110% blended NDR that combines 130% enterprise NDR with 60% SMB NDR tells a misleading story. Segment-level NDR reveals where the product is truly sticky and where retention investment is most needed.
NDR connects to NRR as a closely related metric, and to GRR which provides the retention-only view without expansion. Tracking churn rate alongside NDR clarifies whether the dollar retention is driven by a shrinking but upselling customer base, or by a stable and expanding one.
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Frequently Asked Questions
NDR and NRR are closely related and often used interchangeably. The main difference is measurement approach: NDR typically tracks a specific customer cohort's dollar value over 12 months, while NRR can be calculated monthly or annually using MRR components. In practice, they converge to the same insight — how much revenue from existing customers is retained and expanded.
Related Terms
NRR (Net Revenue Retention)
Net Revenue Retention (NRR) measures the percentage of recurring revenue retained from existing customers over a period, including expansion, contraction, and churn. An NRR above 100% means a SaaS company is growing revenue from its existing customer base without acquiring a single new customer.
GRR (Gross Revenue Retention)
Gross Revenue Retention (GRR) measures the percentage of recurring revenue retained from existing customers over a period, excluding any expansion revenue. GRR can never exceed 100% and reflects the core stickiness of a SaaS product — how much revenue stays without upsells compensating for losses.
Churn Rate
Churn rate is the percentage of customers or revenue lost over a given period. In SaaS, churn rate is the inverse of retention — a 5% monthly customer churn means the company loses 5% of its customer base each month. Reducing churn is the single most effective lever for improving LTV, NRR, and long-term revenue growth.
MRR (Monthly Recurring Revenue)
Monthly Recurring Revenue (MRR) is the predictable revenue a SaaS company earns each month from active subscriptions. MRR normalizes different billing periods — annual, quarterly, and monthly — into one consistent monthly figure, making it the foundational metric for SaaS financial planning.
