What counts as one "request" for serverless platforms?

Each invocation of a serverless function counts as one request. For REST APIs behind a gateway, every HTTP call to the API Gateway endpoint counts. For Cloudflare Workers, each fetch event is one request.

Why does the tool multiply by a variance factor?

Real traffic is uneven — weekends, marketing campaigns, or launches can spike 2–5× the daily average. The variance multiplier lets you model a worst-case month rather than assuming perfectly flat traffic.

Are the free-tier limits shown accurate?

The limits reflect publicly published figures as of mid-2025: AWS Lambda 1M requests/month, Cloudflare Workers 100K requests/day (≈3M/month), Vercel 100K requests/day on the Hobby plan, Netlify 125K requests/month for serverless functions. Always verify against the provider's current pricing page before making financial decisions.

Does this account for request duration or compute costs?

No — this tool focuses on request count only, which is the first billing dimension. Duration-based costs (GB-seconds for Lambda, CPU time for Workers) require separate calculation once you know your p99 execution time.

What is a good requests-per-session number to start with?

A typical single-page app makes 5–20 API calls per page load and navigation. A mobile app might make 3–10 calls per session. If you have analytics, check your average API calls per user session there.

Request Count Budget Calculator

Name: Request Count Budget Calculator
Availability: InStock
Author: Nham Vu

Estimate monthly API or serverless request volume from daily active users and session patterns, then compare against free-tier limits.

Traffic Parameters

Daily Active Users (DAU)

Average unique users per day

Requests per Session

API or function calls per user session

Sessions per User per Day

How many times a user visits/opens per day

Traffic Variance Multiplier

Spike factor for peak days (1.0 = flat, 2.0 = double on peak)

Days in Month

Monthly Request Estimate

Requests / Day

Requests / Month

Peak Day (with variance)

Free-Tier Comparison

Free-tier limits as published mid-2025. Verify current limits on each provider's pricing page.

Calculation Breakdown

Summary

Estimate monthly API or serverless request volume from daily active users and session patterns, then compare against free-tier limits.

How it works

Enter your daily active users (DAU) for a typical day.
Set the average number of API or function requests each user generates per session.
Set how many sessions per day the average user has.
Adjust the traffic variance multiplier to account for weekend peaks or growth.
The tool multiplies DAU × requests/session × sessions/day × variance × 30 to produce a monthly estimate.
Results are compared against published free-tier limits for four major platforms.

Use cases

Validate whether a new SaaS product stays within serverless free tiers during the first months.
Estimate AWS Lambda invocation costs before launch.
Decide between Cloudflare Workers and Vercel for a given request volume.
Model how request counts scale as DAU grows from 100 to 100,000.
Set internal request budgets when building a multi-tenant API.
Check if a traffic spike (product launch, press mention) will exhaust monthly quota.
Plan paid-tier upgrades based on projected user growth.
Audit current usage against free-tier headroom before billing kicks in.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu