The script originally had no back story about Robert, so Denzel Washington contributed much to the character's background and back story, including McACall having obsessive-compulsive disorder (OCD). In addition to his daily physical and fight training before filming, Washington met and interviewed several real-life OCD sufferers in order to gain insights on how to play that disorder correctly.

Slavi refers to Robert as "dedushka" when they meet at the restaurant. This is Russian for "grandfather".

McCall's Craiglist posting, entitled, "Odds Against You? Need Help?" was the same slogan used in the original The Equalizer (1985)'s classified ad.

The film's test screenings received the highest scores and most positive reactions of any R-rated Sony film.

Teri was originally written for an older actress, but Chloë Grace Moretz impressed director Antoine Fuqua so much, he made the role younger. She was 17 years old when the film was released.

Chloë Grace Moretz fought for the role of Teri when she found out it was written for someone of 24. She presented herself so well, Antoine Fuqua immediately made the change.

The nail gun used in the final fight scene is referred to as a tap nailer. It uses a .22-cal. blank to fire nails into steel and concrete on construction sites.

Denzel Washington's first franchise/trilogy movie series.

According to the director, during the research for the role as an underage escort, Chloë Grace Moretz interviewed real-life prostitutes. She met an escort who initially told her to gain weight, because in that profession in order to take care of different men, escorts have to have some flesh. Moretz, who was a minor at the time of filming, changed her diet and gained weight for the role.

Based on the classic television series The Equalizer (1985) starring Edward Woodward.

The screenplay was featured in the 2012 Blacklist; a list of the "most liked" unmade scripts of the year.

Parts of the film were shot at an abandoned Lowe's store in Haverhill, MA.

The watch worn by McCall is a Suunto Core All Black. However, the stopwatch display of the watch in the movie is not the same as in the actual Suunto Core sold commercially, which combines an altimeter, barometer and compass with weather information. When asked if this was a Special Edition, or custom-made watch for the movie, Suunto indicated that it was not, and that more than likely the display on the watch was digitally altered for the movie during post-production.

The film languished in "development hell" for several years before it finally started production. It was originally developed by the Weinstein brothers in 2005. They brought in novelists Michael Connelly and Terill Lee to write the first script with Paul McGuigan to direct. With no progress, in 2010, the rights were then sold to Mace Neufeld and Escape Artists. Paul Haggis was brought in to write another draft with Russell Crowe to play Robert. However, other project commitments resulted in both men dropping out before Denzel Washington saw the script and expressed interest in playing Robert.

Denzel Washington and Jacob Sullivan worked on a screenplay during downtime from shooting.

Chloë Grace Moretz had a Russian teacher as a dialogue coach for the movie. She helped her with little cheat sheets with the phonetics written out of how it should sound.

When McCall contacts the FBI after he takes over the money room and then leaves Detective Masters for the Boston PD, he asks for Agent Mosely. This is an Easter egg to the Robert De Niro and Charles Grodin movie Midnight Run (1988). FBI Agent Mosely was played by Yaphet Kotto.

At the beginning, in Robert's home, when the bookcase is shown, there are leather-bound books. These appear to be from the Franklin Library/Franklin Mint, offered as a set in the '80s.

Denzel Washington admitted in an interview that initially he was reluctant to commit himself to this movie, because of the difficulty finding a director suited for the job. Although pleased that the end result was a box-office hit, he made it no secret that he only made this movie due to contractual obligations.

Denzel Washington's earring holes were digitally edited out for close ups. By the end of the movie when he's sitting in the dark talking to Pushkin, you can see the earring hole in his left earlobe.

Nicolas Winding Refn was the original director, but left the project one month later when he could not agree to contractual terms with the producers on his deal. Rupert Wyatt was the next person approached but he declined, citing scheduling problems (Wyatt also turned down directing Dawn of the Planet of the Apes (2014) for the same reason) before they finally offered it to Antoine Fuqua.

Denzel Washington suggested director Antoine Fuqua for the movie.

McCall asks Andri if his gun is a "Heckler Koch." The gun is actually a Springfield Armory.

Gerard Butler was considered for the lead role of Robert McCall.

As well as appearing in Flight (2012) with Denzel Washington, Melissa Leo also appeared with the original Equalizer in The Equalizer: The Defector (1985).

Denzel Washington was so impressed by director Antoine Fuqua's preparation, especially the character's mindset during each scene, that he told the director to play the lead role instead of him.

The closing credits font is the same used in the television show on which the film is based, The Equalizer (1985).

During his training, Ralphie wears a "Foreigner world tour" T-shirt. The Foreigner song "Urgent" was used to promote the television show The Equalizer (1985) in France.

The Leonard P. Zakim Bunker Hill Memorial Bridge appears throughout the film. It's the main entry/exit route into Boston, and is featured in several movies and television shows set there.

The original Equalizer debuted in The Equalizer: Pilot (1985), aired September 18, 1985, opposite Denzel Washington's own vehicle St. Elsewhere: Remembrance of Things Past (1985).

When Slavi enters his office, he asks his right-hand man Tevi, "Tevi, you collect from that fuck, Dmitri?" Tevi presents Slavi with manila envelope full of cash and says, "Yes. He asked for forgiveness . . . .I told him, 'What am I, Jesus Christ?'" Alex Veadov (Tevi) played Jesus Christ in Jesus Comes to Town (2010).

Denzel Washington and Haley Bennett would later co-star in The Magnificent Seven (2016), also directed by Antoine Fuqua. That film is also a remake, but of movies, not a TV series.

When Masters calls in the bust, he indicates a "10-13". This means "officer needs assistance."

Director Antoine Fuqua's first IMAX feature.

Denzel Washington and Antoine Fuqua's second film together.

Chloë Grace Moretz plays the character Teri, which is also her real-life mother's name.

The tattoo on Teddy's upper back (looks like CMEPTb) is the Russian word "smert" which means "death."

When McCall is on the bus, the coordinates shown for him are N42.3295° W71.8640°.

Teddy's true identity is Nikolai Itchenko.

When Teddy is picked up on the private airport runway by Detectives Masters, Pederson and Remar, Pederson introduces himself as Morgan Pederson. He is played by James Wilcox, who has a brother-in-law named Morgan Peterson.

Antoine Fuqua and Haley Bennett's first film together.

Italian censorship visa #108863 delivered on 7 October 2014.

McCall is never actually shown shooting a firearm. At the restaurant, he twists a henchman's arm forcing him to shoot his boss. Towards the end of the film, McCall only uses the rifle for the scope, and eventually uses a nail gun. Everyone else is neutralized by other creative means.

Robert traps the corrupt Detective Masters in a Series III Jaguar XJ, the model of car that Robert McCall drove in The Equalizer (1985).

McCall's former occupation is described by Susan as "the Agency". This appears to mean that McCall worked for the CIA in some capacity, most likely in their Special Activities Division, where he would have developed the skills and tactics he used throughout the film.

When his co-workers asked what he did before he worked at the Home Mart, McCall says he was a "Pip"-- as in Gladys Knight & The Pips --and he dances a little for them. When Teddy's men take the employees hostage and are getting ready to shoot one of them, the song that McCall plays on the store P.A. system, to get their attention, is 'Midnight Train to Georgia' by the same singing group.

Body Count: 24.

The book that McCall is reading after "The Old Man and the Sea" appears to be "Don Quijote de La Mancha" written by Miguel de Cervantes y Saavedra and published in 1605.

The scene in which Teddy (Nikolai) and the dirty cops meet with "Little" John Looney was filmed at the Boston Sand & Gravel company, the same location in which a scene from The Town (2010) takes place.

Near the end where McCall confronts Pushkin at his mansion in Moscow, the mansion is the same one that was used in Flowers in the Attic (1987).

McCall doesn't curse once throughout the movie.

When Robert and Teri discuss books at the diner, Robert mentions that he is attempting to make his way through the "100 Books Everybody Should Read" list, because it was something his wife also attempted to do before she died. This list contains a book called "Eugene Onegin" by Alexander Pushkin. There is a character by the name of "Pushkin" whom Robert later identifies as the "head of the snake," or the leader of the Russian operation Robert faces. Pushkin is the final target Robert needs to eliminate to complete his mission of "equalization".

The last pull-away shot of the film is an homage to the scene by artist Edward Hopper's painting "Nighthawks." Edward was also the first name of Edward Woodward, who originally played McCall in The Equalizer (1985).

At the end of the movie, Robert McCall sets down Ralph Ellison's book "Invisible Man" (not to be confused with the H.G. Wells science-fiction story). It addresses the issues faced by African-Americans in the early 20th century.

When McCall turns the money over to the police, he writes "follow the money" on one of the $100 bills. In Inside Man (2006), Denzel Washington plays a police officer who gets a clue from the bank robber that says "follow the ring".