---
title: "Downtime — monitoring glossary"
description: "Downtime is any period in which a website or service is unreachable, returns errors, or fails to meet its agreed performance threshold. It is the inverse of…"
canonical: "https://lemwatch.com/glossary/downtime"
source: "https://lemwatch.com"
---

# Downtime

> Downtime is any period in which a website or service is unreachable, returns errors, or fails to meet its agreed performance threshold. It is the inverse of uptime and is the headline figure on most public status pages.

## Definition

 Downtime is recorded when a monitoring system confirms a failure across multiple probes and retry attempts. Best-practice monitoring requires at least two consecutive failed checks from two different regions before declaring an incident, which dramatically reduces false positives caused by local network blips.

 Downtime is then categorised — planned (a maintenance window the operator scheduled) versus unplanned (everything else) — and the duration is what counts against an uptime SLA.

## Why it matters

 A single hour of downtime can cost an e-commerce site tens of thousands of pounds in lost transactions, plus knock-on damage to search rankings and customer trust. Detecting downtime fast and confirming root cause quickly is the entire job of a monitoring platform.

 See it in the product: [Uptime monitoring](https://lemwatch.com/features).


## Related

- [Monitoring glossary](https://lemwatch.com/glossary)
- [Uptime](https://lemwatch.com/glossary/uptime)
- [Incident](https://lemwatch.com/glossary/incident)
- [SLA](https://lemwatch.com/glossary/sla)
- [MTTR](https://lemwatch.com/glossary/mttr)
- [Five Nines](https://lemwatch.com/glossary/five-nines)
- [All monitoring checks](https://lemwatch.com/features)
- [Error Budget](https://lemwatch.com/glossary/error-budget)