Free proxy calculator
Proxy Delay Calculator
Find out how many proxies your retail monitor needs. Pick the site, enter the number of SKUs and your monitor delay in milliseconds, and the calculator returns a proxy count.
Formula
How the monitor delay formula works
The proxy calculator turns your monitor delay into requests per minute. Then it divides that load by the number of requests one proxy can send to the site without getting rate limited.
Target, 5 SKUs, 3,500 ms delay. 60,000 / 3,500 is 17.1 checks per minute per SKU. Times 5 SKUs is 85.7 requests per minute. One proxy carries 6.7 per minute, so you need 12.9 proxies. The calculator rounds up to 15 proxies.
Checks per minute for one SKU
60,000 / delay (ms) A 3,000 ms delay is 20 checks per minute for each SKU you monitor.
Total requests per minute
checks per SKU × SKUs Multiply by the number of SKUs. 20 checks × 50 SKUs is 1,000 requests per minute.
Requests one proxy can carry
60 / site rest time (s) Target rests each proxy 9 seconds, so one proxy carries about 6.7 requests per minute. Amazon rests 45 seconds, about 1.3 per minute.
Proxies needed
total requests / per-proxy requests 1,000 / 6.7 is 150 proxies for Target. The result rounds up to the next multiple of 5.
Proxy sizing
What each input means
A faster delay raises the request count on every SKU you track. If the pool is too small for that load, each proxy hits the site too often and you start to see 429 Too Many Requests errors and blocks. Size the pool first, then lower the delay.
The result covers the monitor only. Checkout tasks, accounts, and cookie harvesting usually run on separate proxies, so add those on top.
Sets the rest time per proxy. Target uses 9 seconds and Amazon uses 45 seconds. These are planning assumptions, not limits the sites publish.
Count each product your monitor checks. On Target, the SKU is the TCIN, the number after A- in the product URL.
The monitor delay from your bot, in milliseconds. 3,500 ms is 3.5 seconds. Do not enter the error delay or retry delay here.
Retail bot guides
Use the result in your bot setup
Running Refract on Target? The Refract Bot Target guide walks through proxy groups, monitor delays, and tasks with this calculator.
For the ISP vs residential decision, sticky vs rotating monitors, account mapping, and backoff during drops, read our sneaker proxies guide.
Proxy calculator FAQ
Answers for sizing a monitoring proxy pool
How many proxies do I need for monitoring?
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It depends on how many SKUs you monitor, your monitor delay in milliseconds, and how often one proxy can safely hit the site. Lower delays and longer SKU lists need more proxies. Enter all three in the calculator to get a count.
What does delay mean in the calculator?
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Delay is the time between two checks of the same SKU, in milliseconds. 3,500 ms is 3.5 seconds. Use the same monitor delay you set in your bot. A smaller delay checks more often and puts more requests on your proxy pool.
What rest times does the calculator use for Target and Amazon?
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The Target preset assumes one request per proxy every 9 seconds, about 6.7 requests per minute. The Amazon preset assumes one request per proxy every 45 seconds, about 1.3 requests per minute. These are planning assumptions, not limits published by the sites.
Why are results rounded to the next five proxies?
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Proxy pools are easier to buy and manage in blocks. Rounding up also gives a small buffer instead of sizing the pool exactly at the calculated limit.
Does the result include checkout tasks and accounts?
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No. The calculator sizes the monitor only. Checkout tasks, account sessions, and cookie harvesting usually run on separate proxies, so plan those on top of the monitor count.
Can I use this as a Shopify proxy delay calculator?
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You can use the same formula for Shopify or other monitors, but the built-in presets are Target and Amazon. For other sites, treat the result as a rough estimate unless you know a safe rest time per proxy for that site.
Need a proxy pool that can carry the load?
Compare dedicated ISP and residential proxy plans for retail monitoring, restock tracking, scraping, and other high-sensitivity workflows.