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A cohort that went from 80,000 to 84,800
Last period the cohort was 80,000 of ARR. The same customers are 84,800 now, after expansion, contraction, and churn. New customers added 20,000 this period. That 20,000 stays out of the ratio.
Prior cohort ARR: 25% lower
Change prior cohort arr to 60,000 while keeping the other example values the same.
Prior cohort ARR: 25% higher
Change prior cohort arr to 100,000 while keeping the other example values the same.
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Quick answer
What does the Net dollar retention calculate?
What share of last period cohort dollars is still here? This calculator uses prior cohort arr, current cohort arr, and new-customer arr to leave out to estimate same cohort, two periods immediately in your browser.
With the values currently entered, the result is 106% — of prior cohort ARR. It also shows cohort change, new-customer arr left out, and cohort plus new customers.
How to use the Net dollar retention
- Replace the example values with your own numbers.
- Review the result and supporting figures as they update automatically.
- Check the formula and assumptions before using the estimate for a decision.
Inputs used
- Prior cohort ARR
- Current cohort ARR
- New-customer ARR to leave out
Net dollar retention formula
Net dollar retention = current cohort ARR ÷ prior cohort ARR. The current figure already includes expansion and is net of contraction and churn. New-customer ARR stays out of both sides.
Assumptions
- The Pure Storage letter to the SEC on September 8, 2025 calculates subscription net dollar retention as current year-end ARR from a prior cohort divided by prior year-end ARR from that same cohort. The current figure includes expansion and is net of contraction and churn. New customers stay out.
- The letter reports 117% for fiscal 2025 and 120% for fiscal 2024. Those figures belong to that company. The percent here is the two cohort amounts you type, for one comparison, rather than a trailing average of monthly rates.
Verify the inputs
Authoritative sources
These sources explain the definitions, factors, or rules behind this tool. Their geographic scope is shown because an official source for one country is not automatically valid somewhere else.
Sources do not endorse Calculum. Check the source date, scope, and your own documents before making a financial, tax, insurance, or reporting decision.
Practical guide
Net dollar retention example and edge cases
Pure Storage calculates subscription net dollar retention by dividing this year’s ARR from a customer cohort by last year’s ARR from those same customers. Expansion stays in the current figure. New customers from this year stay out. The letter reports 117% for fiscal 2025 and 120% for fiscal 2024.
Example: A cohort that went from 80,000 to 84,800
Last period the cohort was 80,000 of ARR. The same customers are 84,800 now, after expansion, contraction, and churn. New customers added 20,000 this period. That 20,000 stays out of the ratio.
- Prior cohort ARR
- 80,000
- Current cohort ARR
- 84,800
- New-customer ARR to leave out
- 20,000
Calculated result106%of prior cohort ARR
Net dollar retention is 106%. The cohort grew by 4,800. Adding the new customers makes 104,800 of ARR, and that combined total is a different question from the 106% rate.
Example results use the default display profile. The calculator above follows your selected country and units.
How to read the result
- The percent is current cohort dollars divided by prior cohort dollars. A result above 100% means the same customers are worth more than they were last period.
- Pure Storage’s 117% and 120% are that company’s reported rates for two fiscal years. The percent on this page is the two amounts you type, for one comparison.
Edge cases worth checking
New logos are inside the current cohort
The letter keeps customers acquired this year out of both the numerator and the denominator. Putting their ARR in the current box raises the rate for a cohort that did not include them.
The two amounts describe different customer lists
Both boxes have to be the same customers. A prior list from one product and a current list from the whole company do not describe one cohort, and the percent mixes two groups.
What changes the result most
Prior cohort ARR
Use a current amount for prior cohort arr. Include fees or recurring costs that belong in the same figure.
Current cohort ARR
Use a current amount for current cohort arr. Include fees or recurring costs that belong in the same figure.
New-customer ARR to leave out
Use a current amount for new-customer arr to leave out. Include fees or recurring costs that belong in the same figure.
Try a different scenario
Small changes show whether the answer is stable or sensitive.
Prior cohort ARR: 25% lower
60,000141.3%of prior cohort ARR
Prior cohort ARR: 25% higher
100,00084.8%of prior cohort ARR
Current cohort ARR: 25% higher
106,000132.5%of prior cohort ARR
Common mistakes
Check prior cohort arr
The Pure Storage letter to the SEC on September 8, 2025 calculates subscription net dollar retention as current year-end ARR from a prior cohort divided by prior year-end ARR from that same cohort. The current figure includes expansion and is net of contraction and churn. New customers stay out. Make sure this matches the number you enter.
Keep new-customer arr to leave out consistent
The letter reports 117% for fiscal 2025 and 120% for fiscal 2024. Those figures belong to that company. The percent here is the two cohort amounts you type, for one comparison, rather than a trailing average of monthly rates. Use the same units and time period throughout the calculation.
Do not rely on one net dollar retention scenario
Run a cautious case and an optimistic case. The range is often more useful than one exact-looking number.
Use this result well
What share of last period cohort dollars is still here?
It does not replace a quote, contract, accountant, or local employment guidance.