How strong is Sanji in One Piece, except being a normal cook?

Sanji is one of the crew's top four fighters along with Luffy, Zoro, and Jinbe. He currently has the third highest bounty in the crew after Luffy and Jinbe. While Luffy usually fights the strongest enemies, Sanji and Zoro usually end up fighting with the enemies considered second to the primary threat. Occasionally, Sanji will take on an opponent explicitly weaker than Zoro's. An example of this is when Sanji fought Jabra of CP9, who had a slightly lower power level than Kaku, who lost to Zoro. The introduction of Douriki during the CP9 Arc is one of the only times in the series that opponents' strengths have been measured numerically. However, Sanji and Zoro's opponents can often be characterised as matching (or countering) their particular combat styles, such as how Sanji fought another leg-style combat user, Mr. 2, during the Alabasta Arc while Zoro fought the blade-focused Mr.1

Although Sanji and Zoro would usually let their rivalry impede their fighting performances, they have proven to be a near-unstoppable force if they agree to cooperate for the battle, as seen when they instantly turned the tables against the Groggy Monsters. As a member of the infamous Vinsmoke Family, Sanji was raised and trained from an early age (along with the rest of his siblings) in the ways of warfare and combat. Similar to his siblings, he also received genetic enhancements from his father, designed to endow him with superhuman abilities. However, due to his mother Sora's intake of a counter-drug, Sanji's genetic modifications were possibly neutralized, thus preventing him from receiving these modifications, and he was born as a “normal” human. Consequently, he could not keep up with his siblings, and his strength did not rise from training. As a result, Sanji could not keep up with the extremely grueling Germa training, but gained and developed a different style of combat with Zeff's help.

Due to years of extremely hard training under Zeff since childhood, Sanji has gained extraordinary superhuman physical prowess, speed, and agility, which enables him to use an array of handstands for a kick-based martial art, which makes him immensely versatile in combat. Sanji has immense physical strength. In his very first appearance, he held Fullbody up by the neck unsupported with one hand before even displaying his lower body strength. In the Arlong Park Arc, he was able to stop Kuroobi from killing Genzo and Nojiko in the water by grabbing onto his leg despite the natural advantage and strength a fish-man receives when submerged. At Little Garden, he hauled a dead Tyrannosaurus Rex through the jungle and back to the Merry with little effort. In Skypeia, when Gan Fall was explaining the Dials, Sanji was shown to be able to lift a huge sledgehammer that appeared to weigh several tons and used it to test the Dial. If the Dial had not absorbed the impact, Sanji would likely smash a hole through Merry's deck. After Luffy and Usopp dueled in Water 7, Sanji was able to easily restrain Chopper in Heavy Point from going to treat Usopp's injuries, in Enies Lobby Sanji alongside Zoro could catch three cannonballs (using Luffy's body) and throw them back with enough strength to destroy a Marine battleship. Sanji could hold Nami above his head and keep her balanced while receiving countless attacks to his body from Absalom. In Zou, Sanji was shown lifting a huge pile of wounded minks with little help. Another example of his physical might is seen when he was able to hold Absalom in place by gripping onto his leg, despite the latter's reinforced and heavy muscular structure and being struck multiple times while doing so.

His training in a kick-based martial arts also grants him colossal leg strength, enabling him to break even the hardest materials and defeat the strongest enemies using the tremendous power of his kicks. He can easily destroy boulders and metal weapons and effortlessly overpower giant sea monsters such as Bananawani and Momoo. Sanji even managed to topple Oars, a monstrous giant, by kicking him in the foot. In an SBS, Oda stated that Sanji's kicking power is 21 Bats (the power to break 21 wooden bats in one kick). After his two years of extremely rigorous training on Momoiro Island, which consists mainly of constantly running away from the Okamas for days regardless of the harshest weather, his leg strength vastly increased. He could break the neck of a Pacifista with only a kick, critically damaging it, and not showing any trouble afterward (something he was not able to do before the timeskip) or being able to break a Seastone cage just with kicks (as seen in Episode of Luffy). He could even smash the exoskeletons of genetically enhanced superhumans such as his brothers Niji and Yonji. His new strength was also shown when Sanji manages to fight on par and briefly overpower Vergo, a Marine Vice Admiral who was able to overpower and defeat Smoker, for a short period of time even after being wounded by attacks from Caesar Clown and having one of his legs broken. His physical power was later recognized by one of the Shichibukai, Donquixote Doflamingo, who was forced to restrain Sanji's movements after the Straw Hat member landed several blows.

Under Zeff's strict tutelage Sanji became an extremely powerful master of a kick based martial art he created named the "Black Leg Style" which is a unique combination of Brazilian Capoeira, French Savate and Korean Taekwondo, able to use powerful kicks with supreme versatility. He has also stated that the reason he fights using is that he does not want to risk damaging his hands as he needs them to cook, thus instead of punches, Sanji incorporates handstands into the Black Leg Style. He is also able to use one-handed handstands, and execute consecutive back handsprings (as seen during his fight with Jabra) to augment the force and range of his kicks. He could easily overpower numerous enemies at once, such as pirates, Marines, and Government agents.

During the time he spent constantly running away from the Okama on the Momoiro Island, he developed both the "Blue Walk" and "Sky Walk", techniques similar to the Rokushiki's technique Geppo, enabling him to swim at great speeds (making him the best swimmer of the crew) and to move through the air (similar to flying), respectively. With "Blue Walk", Sanji can momentarily run underwater. Not only is he not slowed down by the weight of water (as he was during the Arlong Park Arc), Usopp stated that Sanji's speed underwater is on par with a fish-man, who are at their physical prime while underwater. Through the use of "Sky Walk", Sanji can leap to great heights and travel at incredible speed as he makes sonic booms in the air behind him. Sanji used Sky Walk to travel from downtown Dressrosa all the way to edge of Green Bit to intercept Doflamingo in no time at all. In the Wano Country Arc, Sanji could carry Nami, Carrot, Chopper, and Brook simultaneously using Sky Walk.

In the Enies Lobby Arc, Sanji reveals a new ability - Diable Jambe, the power to heat his lower legs to a temperature so high that they glow bright red, by spinning rapidly in place, which causes his attack to be more powerful. The heat of his attacks is so high that contact for even a second could set a person ablaze. Sanji used this ability during his fight with Jabra, in which his normal attacks were not as effective due to his active usage of Tekkai. With the heat of his new ability, Sanji overcame his inability to smash through Tekkai by burning through it instead. By using the technique "Frit Assorti" in Diable Jambe against Oars, Sanji was able to effectively deflect his direct "Gomu Gomu no Bazooka" in order to protect Robin with a single kick.

Diable Jambe has improved to the point that his entire leg is now enveloped in large flames. It is now so powerful and hot that even underwater, he is able to scorch one of the Kraken's tentacles with "Bien Cuit: Grill Shot", severely injuring it. Later at Gyoncorde Plaza, as he was airborne (Sky Walk), he executed another new move called "Poêle à Frire: Spectre", where he stomps his opponents repeatedly with high accuracy and speed. Sanji's Diable Jamble was also able to counter his father's advanced battle gear (which is flame resistant) with ease and when Sanji was about to use "Poêle à Frire" against Judge, the Germa King was forced to resort to using a human shield to overpower his son. Later when forced to fight off his captain, Sanji's Diable Jamble "Concasse" was strong enough to make Luffy pass out when Sanji struck him with it. Later Sanji used "Crosse Strike" along with Luffy's Elephant Gun to counter a lightning attack from Charlotte Linlin.

Kenbunshoku Haki is Sanji's speciality concerning Haki. During his stay on Kamabaka Kingdom, Sanji has trained his Kenbunshoku Haki to an extremely high level. During Fish-Man Island Arc, Sanji could sense Caribou in the Ryugu Palace alongside both Luffy and Zoro. It was stated by Luffy that Sanji possesses Haki when discussing it within the context of members of his crew who could fight Caesar Clown, a Logia user; since Law was referring to the ability to coat themselves in armor, it confirmed Sanji as a Busoshoku Haki user. However, Sanji did not actively display this ability until his fight with his father, when (much to Judge's surprise) he hardened his right leg in order to block one of his father's spear attacks. Later on, he hardened his left leg in order to block Daifuku's genie attack on Carrot. In One Piece Stampede, Sanji uses Busoshoku Haki to free Robin from Smoker's Moku Moku no Mi powers and to successfully bypass the Vice Admiral's intangibility while fighting him.

Germa 66 had created a Raid Suit specifically designed for Sanji to use, which was secretly hidden and given to him as a parting gift during the Vinsmokes' assistance in his and Luffy's escape from Cacao Island. Sanji initially refused to put it on, but donned it while at Wano Country. The suit gives Sanji a black Germa outfit and cape with the number 3 on it, as well as jet-propelled boots. Uniquely, it also gives him a mask to wear over his nose and mouth, and slicks the front of his hair into two parts, one pointing up and one pointing down. Like the other Vinsmokes' Raid Suits, it grants Sanji the ability to fly and strengthen his kicks with propelled boots, and serves as an armor to protect him from attacks. Its unique ability is that it allows Sanji to blend in perfectly with his environment, leaving him invisible to the human eye. This invisibility gives him a great advantage in battle, being able to land surprise attacks on opponents without them seeing him coming. He later uses this ability to sneak into a bathhouse and assist Nami, Robin, and Shinobu in escaping.