Mikoto's power is known as the Railgun. She chose the ability name herself, naming it after her famous finishing move. Her ability belongs to a type of esper powers known as

Electromaster ("Electricity User"): those who can generate and manipulate electricity. Mikoto is the most powerful Electromaster in Academy City. Her maximum output is known to be 1 billion volts. She has also demonstrated enough skill and battle knowledge to fight head on with powerful beings such as a Saint like Brunhild Eiktobel.

Railgun ("Super Electromagnetic Cannon"): Mikoto can fire metal objects at three times the speed of sound by forming parallel currents on both sides of her arm with her electricity. Her railgun has a muzzle velocity of 1030 m/s (2307.2 mph), and can be fired at a rate of 8 shots per minute. She has hinted she can fire multiple coins at once creating a Rail-Shotgun, however this has never been seen. She primarily uses arcade coins as her projectiles for portability, limiting her normal range to 50 meters.

Lightning Attack Spear: Mikoto has the ability to generate a "spear of lightning" originating from her forehead.

Powerful Electromagnetic Pulse: Mikoto has the ability to create magnetic pulses that target the organs

Lightning Strike: Mikoto can call down real lightning using her ability regardless of season. This attack was shown to be powerful enough to cause a city-wide blackout.

Electromagnetism: Mikoto can use electromagnetism to attract and repel metallic materials and use it to her advantage. Examples include creating a make-shift shield out of scrap metal, walking on walls and ceilings, as well as attracting iron particles in the ground around her.

Whip Sword or Iron Sand Sword: Using her magnetic powers, Mikoto can form a "whip sword" by gathering iron sand, manipulating it into a sword that she can lengthen into a whip at will. By making the sand particles of the blade vibrate, she can dramatically increase the weapon's cutting power into something resembling that of a chainsaw.

Cracking/Hacking: Using her electric powers she can hack any electronic device and bypass normal electronic security measures with ease. She can decode the electronic flow of information, like steal the information from a credit card's magnetic strip, as well as directly process a computer's information in binary. This skill also enables her to perform acts such as erasing herself from security footage in real time or taking control of Academy City's roving security robots.

Unique Sensory Perception of Electric-type Espers: As an electromaster, Mikoto is of course able to sense electric, magnetic, and electromagnetic phenomena. She is, however, able to follow the electric and magnetic field lines using her eyes, something that normal electromasters are unable to do with their limited power. She takes this ability one step further by analyzing the reflections of the electromagnetic waves she generates, giving her no blind spots.

Flight: Using formulas similar to those she is using for her Iron Sand sword, Mikoto can fly if she is surrounded by a large amount of atomized water vapor. She manipulated the water vapor forming it into wings using the static electricity from interactions between particles. By using her electric power to induce electrolysis on a large body of water such as the ocean, she can obtain enough hydrogen and oxygen to use as fuel.

Telepathic Immunity: Mikoto has been shown to be immune to the effects of telepathic manipulation due to the electromagnetic barrier created by her AIM dispersion field.

Radar Sense: Mikoto can sense and release electromagnetic waves around her to enable her to see the image of the room three-dimensionally without the use of her sight.

Control of nerves and muscles: Perhaps a reference to her powers being applied to help those with muscular dystrophy. Mikoto is shown to be able to use her powers to take control of her muscles and nerves when they have been rendered ineffective through the use of drugs. The cost of this however is that she requires to constantly use her powers on her body, making her a walking stun gun.