What is Burstable Billing?
Also known as: 95th Percentile Billing
Burstable billing (95th percentile billing) charges customers based on the 95th percentile of their traffic, sampled every 5 minutes over a billing month, discarding the top 5% of data points.
Burstable billing, also known as 95th percentile billing, is a pricing model used by internet service providers and data center operators for bandwidth or transit services. It charges customers based on the 95th percentile of their traffic usage rather than the absolute peak or total data volume.
The method works by recording traffic throughput in bits per second at regular intervals, typically every 5 minutes. Over a billing period (usually a calendar month), the provider collects roughly 8,640 samples (assuming a 30-day month). These samples are sorted in descending order. The top 5% of values (the highest 432 samples) are discarded. The billing rate is set by the next sample, which is the 95th percentile value. This means the customer can burst to their full port speed for up to 36 hours per month without incurring extra charges, as long as the remaining 95% of traffic is lower.
Burstable billing sits between flat-rate unlimited billing and strict committed information rate (CIR) models. It is common for dedicated servers, colocation bandwidth, and transit links. The model rewards customers whose traffic is consistently below a certain level but can tolerate occasional short bursts, making it cost-effective for web hosting, streaming, and enterprise connectivity. It is defined in many provider Terms of Service but is not standardized by a single RFC; its practice is documented in peering and billing agreements.
Key facts
- Traffic is sampled every 5 minutes throughout the billing month.
- The top 5% of samples are discarded; the next highest value sets the billable rate.
- Allows customers to burst to full link speed for up to 36 hours per month at no extra cost.
- Commonly used for dedicated server and colocation bandwidth billing.
- Not an RFC, but widely adopted in peering and transit contracts.
How it works in practice
Related terms
References
More in Hosting Types
Bandwidth
Bandwidth is the maximum rate of data transfer across a network connection, measured in bits per second, and in hosting plans often refers to the total monthly data transfer allowance.
Bare-Metal Cloud
Bare-metal cloud is a service model that provisions dedicated physical servers on demand via API, giving users direct access to hardware without a hypervisor.
Cloud Bursting
Cloud bursting is a hybrid cloud deployment that automatically scales an application from a private cloud to a public cloud during demand spikes.
Cloud Hosting
Cloud hosting provides on-demand access to pooled compute, storage, and networking resources that can be scaled up or down as needed, typically billed per use.
Colocation
Colocation is a service where a provider rents physical space, power, cooling, and network connectivity in a data centre for customer-owned servers and hardware.
Dedicated Server
A dedicated server is a physical machine leased exclusively to one customer, offering full hardware control and no virtualization overhead for high-performance workloads.
Hypervisor
A hypervisor is a software layer that creates and runs virtual machines by abstracting and isolating physical hardware resources for multiple operating systems.
Managed Hosting
Managed hosting is a service where the provider handles server administration, including OS maintenance, security updates, backups, and application support, allowing clients to focus on their core business.
Overselling
Overselling is a hosting practice where providers allocate more resources (bandwidth, disk, CPU) than physically available, assuming customers won't all use their maximum simultaneously.
Reseller Hosting
A business model where one entity purchases web hosting capacity wholesale from a provider and resells it to end customers under its own brand.