NHRL Event Rules

NHRL Combat Area

While similar to other event rules, NHRL tends to be more accepting of exotic and high powered weapons. Our goal is to provide fun, exciting fights and a fair playing field. The sprit of the rules is what is more important than fighting to get to the letter of the law. Good sportsmanship is always required.

Information regarding violation of these rules and other important information can be found on the Safety page.

Bot Design Rules and Limits

Weight Class Specific Rules

Special Rules for Rocket Motors & Flames

Bots that use weapons such as rocket motors, or weapons that include the use of a flame, must abide by additional rules. See the sections on Fire and Flame-Based Weapons and Rocket Motors on the Safety Page.

20 Minute Ready Rule

All robots are guaranteed a minimum of 20 minutes between fights. When there are many bots in event the time between matches may be up to an hour or two between your robots last match and its next match. As the number of robots dwindles the time between your robots last match and next will get shorter. The minimum time it can be is 20 minutes. This time is per bot, not per builder. If you are entering multiple bots it is on you to manage your time. Robots that are not ready will forfeit their matches.


All fights are observed by a team of 3 judges. In the event that a fight lasts the entire 3 minutes (or 3.5 minutes for encore), the match decision goes to the judges. There is open deliberation between judges after the fight and they will announce their final decisions, declaring who they consider the winner. Judges primarily are looking for aggression and control of the match.

Judges are typically ex-competitors and previous bot builders.

Judges decisions are final.

Matches will be judged across 3 categories of equal weight;

  • Control - How controllable this robot in how it translates across arena and in how it attacks
  • Aggression - How much does this robot act as the aggressor and dominate the match flow
  • Damage - How much damage does this bot do its competitor.

Modular Bots

Modular bots are robots that can change offensive or defensive features depending on who they up against in the tournament. Repairs and replacing broken components of your robot don't count as a modular robot. If you are changing less than 10% of your robot weight and none of it is powered, it’s not considered a modular robot! Like all other bots you still need to bring it to the green room in its final ready state.

  • No more than 50% of the entry weight (this includes all weight bonuses) budget can change.
  • All versions of the modular robot must pass safety before being put in the ring.
  • If you are taking advantage of a weight bonus all versions of your module configuration must also be able to earn that weight bonus.
  • If you bring spare robots your modules must be interchangeable between spares.
  • You can only bring entries you intend to fight into the green room. Swapping of modules or bots at the cage is not allowed.
  • Any competitors that have qualified for the finals before July 2021 can keep their legacy configuration and aren't limited by the 50% weight rule. However all other rules apply.

Spare Robots

Bringing exact duplicate copies of your robot is allowed. In order to count as the same robot spares must be as close to exact copies as possible. This is a common way many competitors speed up repairs. All copies must pass safety before competing. If you are bringing multiple robots in a modular configuration you should be able to demonstrate the modules could be swapped between robots at any time. If you can't, then it doesn't qualify as the same robot.

Spare Batteries

Bringing Spare Batteries is HIGHLY encouraged. Bots get a minimum of 20 minutes in between matches for repair and recharge. Rarely is this enough time to recharge a fully dead battery. Bringing spare batteries is highly recommended! If you let the organizers know your battery size and connector type one week in advance (robot@nhrl.io), we will gladly provide you with a spare battery for your bot for free. NHRL has a strong preference for XT style connectors XT90/60/30s.

General Fight Rules

Duration 3 Minutes or 3.5 minutes if an encore is called for by the officials.
Knock Out Any robot unable to show controlled locomotion after 10 seconds is considered disabled and will be considered a knock out.
Tap Out Any competitor can forfeit the match at any time by pressing the large red button on their button box. This is considered a tap out, and counted as a loss. The other competitor must stop attacking immediately; continuing to attack after tap out will be viewed as unsportsmanlike.
Encore If a match is particularly exciting officials may poll the audience in the final minute and decide to add an Encore extending the match by 30 seconds. Only one Encore can happen in any single match.
Hazard If officials deem a robot to be a hazard to the crowd or a robot is doing sustained damage to the arena, the judges may prematurely end the match at any time. Purposefully destroying the arena may result in a forced forfeit of the match.
House Robots The house robots serve as an in ring camera, and referee that can sometimes unstick and disentangle bots. House robots will unstick stuck robots each once per match. If stuck a second time the robot must unstick itself or it will lose if unable to show controlled motion.
Safety Officials reserve the right to disqualify any competitor for failing to follow basic safety. All robots with a kintetic weapon should have a weapon lock. The lock should not be removed until both bots are in the arena and the doors are about to close.
Sportsmanship Officials reserve the right to KO or Disqualify any bot or team for unsportsmanlike conduct.
Final Decisions All judges decisions are final and not subject to review.
Be Ready Only 20 minutes of pit time is guaranteed between matches. This usually only comes into play when there are few robots remaining in the bracket. Early on time between matches can be an hour or more.

Spirit of the Rules

More important than winning or any prize is that the events are fun and enjoyable for all. Short of the weight rule, the rules exist to set the sprit more than a specific worded law. AKA Don't be a lawyer about it. We have a bias to fight robots that show up. If you build something new that you think plays to the edge of rules, show up and tell us why it should be allowed. Odds are we will let you fight, we love new creative ideas.

If you want to speak to an official about potential new bot designs that you feel may be on the edge of the rules, you can contact staff by emailing robot@nhrl.io.

Pushing the Rules

These rules describe the absolute limits of what can be done. There is much that is allowed at NHRL that might not be at other events. We actively encourage competitors to think creatively and imagine new robot designs. The following are examples of things are are perfectly legal within the NHRL rules

You are ALLOWED to do this at NHRL

  • Robots that use fire or heat as weapon
  • Robots powered by an internal combustion engine
  • Robots that use compressed gasses
  • Robots that are made of fabrics or soft bodies
    • It is okay to use materials which may entangle spinning weapons.
    • Materials must not be used solely as an entanglement device.
  • Robots that will keep fighting even if their batteries are on fire
  • Robots that are crusher robots
  • Robots that fly or hover