The diameter of 2024 YR4 has not been measured, but it can be estimated from its brightness (absolute magnitude) using a range of plausible values for its surface reflectivity (geometric albedo). If 2024 YR4 reflects between 5% and 25% of visible light, then its diameter is between 40 and 90 m (130 and 300 ft). NASA estimates a diameter of 54 m (177 ft) for an assumed geometric albedo of 0.154. These estimates make 2024 YR4 around the same size as the asteroid that caused the 1908 Tunguska event or the iron–nickel asteroid that created the Meteor Crater in Arizona 50,000 years ago, and significantly smaller than the Dimorphos target of the DART asteroid redirection test. The diameter and albedo of 2024 YR4 can be further constrained with thermal infrared observations, radar observations, an occultation of a star, or direct imaging by a spacecraft.

The mass and density of 2024 YR4 have not been measured, but the mass can be poorly estimated with an assumed density and the estimated diameter. Assuming a density of 2.6 g/cm , which is within the density range for stony asteroids such as 243 Ida, the Sentry risk table estimates a mass of 2.1×10 kg with an assumed diameter of 54 meters.
Preliminary spectroscopic analysis from the Gran Telescopio Canarias and Lowell Discovery Telescope suggests that 2024 YR4 is either an S-type (17% of the asteroid population) or L-type asteroid, both of which point to a stony composition.

Photometric observations by the Very Large Telescope (VLT) and the La Silla Observatory's 1.54-meter telescope indicate 2024 YR4 has a rotation period near 19.5 minutes. The brightness of 2024 YR4 varies by 0.42 magnitudes as it rotates, indicating it has an elongated shape. The VLT has also observed 2024 YR4 at multiple phase angles from 5° to 35°, which would allow for the construction of a phase curve which can constrain the asteroid's surface properties.

2024 YR4 orbits the Sun on an elliptical orbit that crosses Earth's orbit, making it an Apollo-type near-Earth object. The asteroid has an orbital period of about 3.99 years and an orbital inclination of 3.41 degrees with respect to Earth's orbit (ecliptic).

The asteroid came to perihelion (closest approach to the Sun) on 22 November 2024. The asteroid made a close approach to Earth on 25 December 2024, two days before its discovery. During this encounter, the asteroid passed 828,800 km (515,000 mi; 2.156 LD) from Earth and then 488,300 km (303,400 mi; 1.270 LD) from the Moon. The asteroid will make its next close approach to Earth around 17 December 2028, when it will pass 7,940,000 ± 484,000 km (4,934,000 ± 301,000 mi; 20.66 ± 1.26 LD) from the planet. The 2028 encounter will provide astronomers the opportunity to perform additional observations and extend the observation arc by four years. This will greatly improve calculations of 2024 YR4's orbit in preparation for its close approach around 22 December 2032.

Calculations using the observation arc of 45 days as of 10 February 2025 find that 2024 YR4 has a 1-in-48 (2.1%) chance of impacting Earth on 22 December 2032 around 14:02 UT. The nominal closest approach to Earth is on the 22nd at 10:42 UT (with an uncertainty in the closest approach time of about 15 hours) at a distance of 170,000 kilometres (110,000 miles; 0.44 lunar distances), with a 3-sigma uncertainty of 712,000 kilometres (442,000 miles; 1.85 lunar distances). Due to 2024 YR4's size and greater-than-1% impact probability, it is rated at Torino scale level 3, which has prompted the International Asteroid Warning Network to issue a notice on 29 January 2025. This is the second-highest Torino scale rating an asteroid has ever reached, behind 99942 Apophis which briefly ranked Torino scale level 4 in late 2004. NASA gives a Palermo scale rating of −0.34 for 2024 YR4, which corresponds to an impact hazard of 45.7% of the background hazard level. The European Space Agency gives a Palermo scale rating of −0.34 with an impact probability of 2.02%, while NEODyS gives −0.36 with an impact probability of 1.62%.