As with other robot combat competitions, Robot Wars competitor robots were split into several weight classes (also known as weight categories). Although the first series included robots from various weight classes, subsequent series generally only included heavyweight robots in the main competition, and robots from other weight classes generally only competed in their own small competitions. Because Robot Wars was created in America, the weights were originally dictated in pounds, and converted to kilograms without rounding. The original weight limit for each class was:
- Featherweight: 11.4kg
- Lightweight: 22.7kg
- Middleweight: 45.4kg
- Heavyweight: 79.4kg
- Super Heavyweight: 154kg
Some competitors in Series 1-3 were given some leniency. Barry from Series 1 also notably broke the limit by weighing 116.9kg, which would still render the robot a super heavyweight to this day.
The weight limits were increased from Extreme 1 onwards, and an antweight class was added. The new weight limits were:
- Antweight: 150g
- Featherweight: 12kg
- Lightweight: 27kg
- Middleweight: 54kg
- Heavyweight: 100kg
- Super Heavyweight: 200kg
To encourage creativity, walkerbots were allowed to enter one weight class below their actual weight, or weigh up to 200kg in the heavyweight competition (160kg prior to the increased limits). Super heavyweight walkers received no weight bonus. A subdivision of walkerbots, the shufflebot, held the 200kg weight limit until Series 6, where it was reduced to 150kg, but notably still ignored by Ansgar.
The weight limit was increased again in Series 8 of Robot Wars, which only featured one weight class. The weight limit of walkerbots and shufflebots was also altered.[1]
- Heavyweight: 110kg
- Heavyweight walkerbot: 135kg
- Heavyweight shufflebot: 120kg
In Series 10 the featherweight class was reintroduced and the main weight limit for that class increased. Meanwhile, the weight limits for heavyweight walkerbots and shufflebots were both increased.[2]
- Featherweight: 13.6kg
- Featherweight walkerbot: 17.6kg
- Featherweight shufflebot: 15.1kg
- Heavyweight walkerbot: 145kg
- Heavyweight shufflebot: 125kg
Champions
From Series 2 onwards, the main competition was intended solely for heavyweight competitors, which meant that robots from other weight classes had to enter their own separate competitions. Series 2 featured competitions for all the other weight classes (except antweight), but these competitions became less frequent in subsequent series and were mainly restricted to special events on Robot Wars Extreme.
Antweight
- Main article: Antweight Championship
- Extreme Series 1: Combat Ant
- Extreme Series 2: Anty B
Featherweight
- Main article: Featherweight Championship
- Series 2: Demolisher
- Series 3: Event cancelled
- Extreme Series 1: Beef-Cake
- Extreme Series 2: Argh!
- Series 7: DTK
Lightweight
- Main article: Lightweight Championship
- Series 2: Slippery Strana
- Series 3: Event cancelled
- Extreme Series 1: Event cancelled
- Extreme Series 2: Typhoon Thunder
Middleweight
- Main article: Middleweight Championship
- Series 2: Hard Cheese
- Series 3: Event cancelled
- Extreme Series 1: Typhoon
- Extreme Series 2: Typhoon
- Series 7: Typhoon
Heavyweight
- Main article: UK Championship
- Series 1: Roadblock
- Series 2: Panic Attack
- Series 3: Chaos 2
- Series 4: Chaos 2
- Series 5: Razer
- Series 6: Tornado
- Series 7: Typhoon 2
- Series 8: Apollo
Super Heavyweight
- Main article: Super Heavyweight Championship
- Series 2: Kick Robut
- Series 3: Event cancelled