If you struggle to understand offside or wonder why goalkeepers can't pick up the ball with their hands after a deliberate back-pass from a teammate, this article is for you.

Despite simplicity being the reason for this sport's success around the world, the truth is that the laws governing football have not always been as we know them today.

Faced with the urgent need to standardise football rules for international matches, in the early 1880s those responsible for the game came together to define a set of rules that everyone could follow.

That is how the International Football Association Board (IFAB) came about — and with it, the first unified set of Laws of the Game.

What are the main rules of football?

IFAB currently defines 17 laws of football, published in the document Laws of the Game (LOTG). The most recent edition also includes changes that came into force at the FIFA Club World Cup from 14 June.

These updates include adjustments to the goalkeeper's time in possession, the use of VAR, and new offside rules.

What must the pitch look like?

The pitch must be rectangular, with minimum dimensions of 90x45 metres and maximum dimensions of 120x90 metres. For international matches, the length increases to 110–120 metres and the width to 64–75 metres.

Lines must be no more than 12 cm wide, with the centre circle having a radius of 9.15 metres.

The six-yard box sits 5.50 metres from the goal, while the penalty area, where penalties are awarded, sits 16.50 metres out. Goal arcs and corner markings follow regulated measurements, ensuring international uniformity.

What are the rules for the ball and the players?

The ball must be spherical, made of rubber or approved material, with a circumference of 68–70 cm and a weight of 410–450 g.

Each team plays with 7 to 11 players, including the goalkeeper, and can make a limited or pre-agreed number of substitutions. The kit must be safe: shirt, shorts, socks, shin guards and footwear, with no jewellery or dangerous objects permitted.

What are the roles of the referee and assistants?

The referee has full authority over the application of the rules and may stop, suspend or end the match. They may also reverse a decision if they realise an error was made before play resumes.

Assistant referees indicate when the ball leaves the field, which team is entitled to throw-ins or corners, offside situations, substitutions, and infringements not visible to the main referee.

How long does a match last and what are the restart rules?

A match lasts 90 minutes, divided into two 45-minute halves, with a maximum interval of 15 minutes. Additional time is added to account for stoppages.

The match begins with a coin toss and kick-off; the same applies to restarts following a dropped ball, corners, throw-ins or goal kicks.

The dropped ball now applies to restarts where the ball was outside the area during a stoppage, ensuring fairness in possession.

How do goals and offside work?

A goal is valid when the ball fully crosses the goal line, provided no prior infringement has occurred.

Offside is an infringement when the player's entire body is ahead of the second-to-last defender and they are involved in play — receiving the ball from a teammate — except when the ball is received from a goal kick, throw-in or corner.

IFAB is also testing changes to promote attacking football and encourage the creation of goalscoring opportunities, with adjustments being trialled in international competitions.

What are the recent changes introduced by IFAB?

Among the key changes are:

• Goalkeeper time in possession: increased from six to eight seconds, with the referee signalling a corner instead of an indirect free kick when exceeded;

• VAR decisions: referees may announce them publicly out loud, increasing transparency;

• Body cameras: being tested by FIFA in official matches;

• Dropped ball: in certain situations, guarantees that the team in possession retains the right to restart.

What are the fouls and disciplinary sanctions?

Fouls are penalised with direct or indirect free kicks, or penalties. A recent rule prohibits the goalkeeper from handling the ball after a deliberate back-pass with the feet from a teammate, punishable by an indirect free kick.

Yellow and red cards follow the traditional application: two yellows result in a red, and the referee may issue a straight red for serious infringements.

This season, the Primeira Liga also introduced the purple card, shown in cases of player concussion; the decision is made exclusively by the medical team and allows an immediate substitution without penalising the team.

How do free kicks, corners and throw-ins work?

• Free kick: the ball must be stationary; it cannot be played again before touching another player.

• Penalty kick: taken from 11 metres, with the goalkeeper on the line and the rest of the players outside the penalty area; additional time is granted if necessary.

• Throw-in: taken with both hands, ball above the head, feet on or behind the touchline.

• Goal kick: restart taken by the defending team; a direct goal can only be scored against the opposition.

• Corner kick: awarded when the ball last touches a defending player before going out; taken with the feet.

Conclusion: how to follow and respect the rules of football?

Football is a universal sport, but one full of technical and regulatory nuances. With the latest IFAB changes — including goalkeeper possession time, VAR and offside — matches are becoming fairer, more transparent and more attacking.

The introduction of the purple card and other disciplinary measures offer greater protection for players, while classic rules continue to underpin the way the game is played. Understanding these laws not only helps you play better, but also allows you to appreciate every match with complete knowledge.

Following the rules means respecting the sport and helping to ensure football continues to be played safely, enjoyably and competitively around the world.