How to use this calculator
- Enter average pages and per-page stage times.
- Add document-level model and validation overhead.
- Set parallel workers and a realistic utilization target.
- Enter the queue size and calculate.
#896 · AI & Technology Tool
AI Document Processing Latency Capacity Calculator
Plan whether an AI document pipeline can meet a turnaround target before deploying more workers. This calculator combines page-level OCR and extraction time with document-level model and validation time, then applies parallel worker capacity and utilization. It reports estimated latency for one document, sustainable documents per hour, and the time required to clear a specified queue. Network delay and vendor throttling can be included as document-level overhead.
Calculator
Pipeline timing assumptionsFormula
Service time = Pages × (OCR sec/page + Extraction sec/page) + Document overhead
Capacity/hour = Workers × 3,600 × Utilization ÷ Service time
What the result means
Hourly capacity is the sustainable processing rate at the selected utilization. Service time excludes queue waiting, while queue clearance assumes no new arrivals.
This is a deterministic capacity estimate. Tail latency, uneven document sizes, rate limits, and worker failures can increase real turnaround time.
Example calculation
With 10 pages, 1.2 seconds OCR, 0.8 seconds extraction, and 5 seconds overhead, service time is 25 seconds. Eight workers at 80% utilization process 921.6 documents/hour; 1,000 queued documents take about 1.09 hours.
Tips for better results
- Use p50 and p95 stage measurements in separate scenarios.
- Do not set utilization to 100% when arrivals are variable.
- Measure rate-limit waiting as overhead.
- Segment unusually large documents.
- Compare queue clearance with the required SLA.
Frequently asked questions
Does single-document latency include queue waiting time?
No. It is the service time after a worker starts processing; actual end-to-end latency also includes time waiting in the queue.
Why apply utilization below 100 percent?
Spare capacity helps absorb variable arrivals, long documents, retries, and brief worker interruptions.
Should model API rate-limit delays be included?
Yes. Add recurring wait time to document overhead or reduce effective worker capacity to reflect the limit.
Can OCR and extraction run in parallel?
This formula adds their times. If they overlap in your architecture, enter the measured combined critical-path time rather than both full durations.
What happens if new documents arrive while the queue is clearing?
The displayed clearance time assumes no new arrivals. Subtract the arrival rate from hourly capacity before estimating a live queue drain time.
Related calculators
Latency model components
| Component | Scaling | Unit |
|---|---|---|
| OCR | Per page | seconds/page |
| Extraction | Per page | seconds/page |
| Overhead | Per document | seconds/document |
| Parallelism | Whole system | workers |