Units & conversions

Most bad cost estimates start as unit mistakes. Convert explicitly before you model pricing tiers.

Quick conversions

  • Mbps �?MB/s: divide by 8 (megabits to megabytes).
  • GB �?GiB: GB is decimal (10^9 bytes). GiB is binary (2^30 bytes). 1 GiB �?1.074 GB.
  • Per 10k vs per 1M: normalize pricing units first (a 100× error is common).
  • Hours/month: for estimates, 730 is a typical month; adjust for schedules.

Throughput �?monthly GB

A safe workflow for transfer estimates:

  1. Convert Mbps to MB/s (divide by 8).
  2. Multiply by a utilization factor (average / peak).
  3. Multiply by seconds/day and hours/day (or 730h/month for always-on).
  4. Convert MB to GB (divide by 1000 if your pricing is per GB).

Example: 50 Mbps average, 12 hours/day �?(50/8) MB/s × 12 × 3600 × 30 / 1000 �?810 GB/month.

How to get your inputs

  • Requests: load balancer metrics, API gateway metrics, or application dashboards (RPS).
  • Transfer: CDN origin egress, load balancer processed bytes, or VPC flow logs summaries.
  • Storage: allocated vs used (billing often charges allocated, monitoring often shows used).
  • Time: scheduled uptime (work hours) vs always-on (730h/month).

Common mistakes (and how to avoid them)

  • Mixing bits and bytes: “Mb�?is bits; “MB�?is bytes. Double-check the capital B.
  • Using GiB numbers with GB pricing: convert before multiplying by $/GB.
  • Assuming 100% utilization: average throughput is often far lower than peak.
  • Forgetting per-request unit size: “per 10k�?vs “per 1M�?changes everything.
  • Using the wrong month length: scheduled workloads rarely run 730 hours.

Validate after you deploy

  • Compare estimated monthly GB to actual “bytes transferred�?in your provider metrics.
  • In billing/Cost Explorer, group by usage type and confirm the unit (GB, requests, hours).
  • Re-check after traffic changes: launches, batch jobs, and incident retries can shift averages fast.

Apply conversions to cost drivers

  • Convert throughput to monthly GB before using transfer or CDN calculators.
  • Normalize request units (per 1k, per 10k, per 1M) before multiplying by volume.
  • Convert GiB to GB if pricing is decimal, then use the storage calculators.
  • Use a consistent hours/month assumption across all compute estimates.

Scenario planning

  • Baseline: average throughput and request rates with normal utilization.
  • Peak: higher throughput and request volume during launch or incident weeks.
  • Scheduled workloads: compare 730 hours vs your real schedule.
  • Unit drift: keep a checklist for GB vs GiB and per-1k vs per-1M.

Validate after changes

  • Confirm units in billing exports match your calculator inputs.
  • Re-check conversions after switching providers or regions.
  • Validate monthly totals against a real week of metrics.
1 unit tools

Sources

Assumptions: pricing pages use the provider’s billing units (often decimal GB). Convert your monitoring numbers to the same unit before multiplying by rates.

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