Service Level Agreement (SLA) breakdown

Published: Feb 28, 2025

Last updated: Mar 2, 2025

Introduction - What is SLA?

If you work in tech you might've heard the term Service Level Agreement (SLA) and thought what in tarnation is that? A SLA is a contract between a service provider and a customer that outlines the expected level of service the provider must deliver. It defines the performance standards, responsibilities, and consequences if those standards aren't met.

Example

Imagine you're a business that uses a cloud storage service. The SLA between you and the cloud provider might specify:

Uptime Guarantee: The cloud service will be available 99.9% of the time.

Response Time: If there's an issue, the provider will respond within 1 hour.

Resolution Time: Critical issues will be resolved within 4 hours.

Compensation: If the provider fails to meet these standards, you'll receive a credit on your bill.

SLA table

Below is a table of common availability levels and their related unavailability based on various time ranges.

Availability level	Allowed unavailability
(uptime)	per year	per quarter	per month	per week	per day	per hour
90%	36.5 days	9 days	3 days	16.8 hours	2.4 hours	6 minutes
95%	18.25 days	4.5 days	1.5 days	8.4 hours	1.2 hours	3 minutes
99%	3.65 days	21.6 hours	7.2 hours	1.68 hours	14.4 minutes	36 seconds
99.5%	1.83 days	10.8 hours	3.6 hours	50.4 minutes	7.20 minutes	18 seconds
99.9%	8.76 hours	2.16 hours	43.2 minutes	10.1 minutes	1.44 minutes	3.6 seconds
99.95%	4.38 hours	1.08 hours	21.6 minutes	5.04 minutes	43.2 seconds	1.8 seconds
99.99%	52.6 minutes	12.96 minutes	4.32 minutes	60.5 seconds	8.64 seconds	0.36 seconds
99.999%	5.26 minutes	1.30 minutes	25.9 seconds	6.05 seconds	0.87 seconds	0.04 seconds