Scrape Interval Calculator

Determine the right Prometheus scrape interval balancing granularity and storage cost.

About Scrape Interval Calculator

Scrape load = targets ÷ interval, and multiplying by average scrape duration gives the effective number of concurrent in-flight scrapes: concurrent_load = (targets / interval) × avg_duration. Comparing this against your Prometheus instance's sustainable scrape capacity (bounded by scrape_timeout, network fan-out, and worker concurrency) shows whether your current interval/target combination is safe or will cause scrape delays and gaps.

Formula

samples_per_day = (86400 / scrape_interval_sec) × targets

scrape_interval_sec: Seconds between scrape attempts
targets: Number of scrape targets

Worked example

With the default values below, Scrape Interval Calculator returns Scrape Capacity Utilization of 3.2%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Scrape Targetsaccepts 1–1,000,000 targets: 300 targets
Scrape Intervalaccepts 1–3,600 seconds: 15 seconds
Average Scrape Durationaccepts 1–60,000 ms: 80 ms
Scrape Capacityaccepts 1–1,000,000 scrapes/sec: 50 scrapes/sec

Results

Scrape Capacity Utilization: 3.2%
Concurrent Scrape Load: 1.60
Scrapes per Second: 20.00 /s
Max Targets at This Interval: 9,375 targets

Step by step

1Scrapes per second: targets ÷ interval= 20.00/s
2Concurrent scrape load: rate × duration= 1.60 concurrent
3Capacity utilization= 3.2%
4Max targets sustainable at this interval= 9375 targets

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What happens if concurrent load exceeds capacity?

Scrapes start queuing and some may exceed `scrape_timeout`, resulting in missed/failed scrapes that show up as gaps in your metrics and `up == 0` for affected targets during the overload window.

Should I lower the scrape interval or add more Prometheus capacity first?

It depends on your goals — if you need higher-resolution data, scale capacity (more Prometheus replicas/shards, faster hardware, network tuning); if the current resolution is already sufficient, raising the interval is usually the cheaper fix.

Why does scrape duration matter as much as target count?

A target that's slow to respond (large metrics payload, slow app) ties up a scrape worker longer, so a smaller number of slow targets can create the same concurrent load pressure as many fast targets.

How do I measure real scrape capacity?

Watch `prometheus_target_scrapes_exceeded_sample_limit_total`, `scrape_duration_seconds`, and `up` metric flapping under load — sustained increases in scrape duration as target count grows is a sign you're approaching capacity.