Bandwidth cost as traffic grows
What egress costs if request volume doubles, 5x or 10x.
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API & Backend Cost
API Bandwidth Calculator
Estimate the data your API moves and what egress will cost. Enter monthly requests, average payload size and egress rate, and see total GB, TB and the monthly bill.
Data transferred / month
$0
In terabytes—
Estimated monthly cost—
Cost per 1,000 requests—
Requests per month—
Annual data—
What the API Bandwidth Calculator does
Bandwidth is one of the most underestimated costs in running an API. Every response you send counts as egress, and cloud providers charge per gigabyte that leaves their network. A small payload feels free, but multiply it by millions of requests and the data volume, and the bill, becomes significant.
This API bandwidth calculator multiplies your monthly requests by the average payload size to get total data transfer in gigabytes and terabytes, then applies your egress rate for a monthly cost. It also projects how bandwidth spend grows as traffic climbs.
Heads up on pricing. The rates built into this tool are public list estimates for July 2026 and can change without notice. Providers also offer batch discounts, prompt caching and volume tiers that lower real costs, so treat the output as a planning estimate, not a quote.
The formula
data per month (GB) = requests × avg KB ÷ 1,000,000
bandwidth cost = data per month × egress price per GB
bandwidth cost = data per month × egress price per GB
Worked example
For 20,000,000 requests a month at 80 KB average payload, data is 20,000,000 × 80 ÷ 1,000,000 = 1,600 GB, or 1.6 TB. At $0.09 per GB that is about $144 a month in egress.
Ways to lower your API and backend costs
- Serve responses through a CDN. Cached, edge-delivered responses cut egress cost and take load off your origin.
- Compress payloads. gzip or brotli plus trimming unused JSON fields reduces bandwidth on every single request.
- Cache common responses. Avoid recomputing identical results for repeated reads, which lowers both compute and request fees.
- Reduce chatty designs. Combine several small calls into one batch endpoint or a single GraphQL query to cut request volume.
- Right size and autoscale. Match capacity to real peak traffic instead of paying for servers that sit idle most of the day.
Frequently asked questions
How do I calculate API bandwidth?
Multiply monthly requests by the average payload size in KB, then divide by one million to get gigabytes. Multiply by your egress rate for the cost.
What counts as egress?
Any data leaving the provider network, which for an API is your responses to clients. Inbound requests are usually free or much cheaper.
How can I reduce bandwidth cost?
Compress responses with gzip or brotli, trim unnecessary fields, paginate large results, and serve static or cacheable content through a CDN with lower egress rates.
Is a CDN cheaper for bandwidth?
Often yes. CDN egress can be a third to a half of direct cloud egress, and caching means many responses never touch your origin.
Are the rates accurate?
They are 2026 estimates. Egress pricing varies by provider, region and volume, so confirm your rate for an exact figure.