What is the difference between standard firewall and UTM?

Standard Firewalls having some limites Features of Network Security and now Unified Threat Managament is bundle of all security package like Antispam , Antivirus etc. 

Standard firewalls controls incoming and outgoing network traffic based on certain set of rules mostly depended upon IP address and Ports.

Whereas UTM is more comprehensive network security solution as standard firewall/Next generation firewalls are only a part of UTM security suite. UTM can be configured to act as Email Security (Email Scanners), URL filtering (web proxy), Wireless Security, Web application firewall (NGFW with application intelligence) and virtual private networks (VPNs). So much information feed of network flow into a single device further enables its events co-relation engine to provide with more conclusive and accurate security logs.

Standard Firewall is with Limited features (network, Email etc) with different Modules.

UTM comes Full Bundle solutions ( Email, network, Application control, Web control etc).

Basic firewall is just a component of UTM. It can be interchaged if you are comparing next generation firewall vs UTM. 

UTM can be firewall, web filter , email gateway

firewall allows or deneys traffic from IP to IP address on specific port; mainly works at the network layer

UTM consists of a firewall and other features expands to the application layer

web security (denying porno sites and/or social media)

Mail security (detecting spam and viruses in attachments)

IDS/IPS Intrusion Detection/Prevention system

next generation firewalls as UTMs but looks deeper into traffic to metigate attacks as Advanced Persistant threats APTs, much higher  throughput rates due to dedicated ASICS

Firewalls basically work on an applied set of rules. It matches all incoming and outgoing data packets with the ones in the database in order to figure out whether they are harmful or not.

Unified Threat Management Appliance is a much more powerful security tool as compared to a standard firewall.It needs to be connected to the main network and works in order to provide maximum security against all incoming malware. also it has different feature such as DLP , LB , Mail gateway ,IPS,  and so on 

UTM have bundle of solutions available like : 

1. Mail Security (Mail Gateway)

2. Antivirus scanning

3. Web Protection

4. VPNs