Which Are the Charges on the Different Subatomic Particles: A Field Guide to +2/3, −1, and the Neutral Pieces Between

The charges on the different subatomic particles are quantized in units of the elementary charge e (about 1.602 × 10⁻¹⁹ coulombs): protons carry +1e, electrons carry −1e, neutrons carry 0, up-type quarks carry +2/3e, down-type quarks carry −1/3e, and neutrinos carry 0. Composite particles sum their constituents: a proton is +2/3 + 2/3 − 1/3 = +1, and a neutron is +2/3 − 1/3 − 1/3 = 0. Every charge you can isolate in a lab is an integer multiple of e, yet the quarks inside never appear alone.

Charge quantization and the basic ledger

Charge is not a continuous property you can tune. It comes in discrete chunks tied to the Standard Model's gauge structure, and the electron's charge sets the unit. Each particle's charge is fixed by its identity, not by its speed, temperature, or environment.

The bookkeeping is additive in the simplest possible way. A bound state's charge equals the sum of its parts' charges, with antimatter flipping the sign. A proton is two up quarks and one down quark. An antiproton is two anti-ups and one anti-down, giving −2/3 − 2/3 + 1/3 = −1. A neutron is one up and two downs: +2/3 − 1/3 − 1/3 = 0.

That arithmetic is why atoms are neutral. A carbon nucleus has six protons (+6) and six neutrons (0); six orbiting electrons (−6) cancel it exactly. The cancellation is not approximate. It holds to at least one part in 10²¹ for charge neutrality of bulk matter, per precision tests of the equivalence principle.

The deeper point is that charge conservation is absolute in the Standard Model. No known process creates or destroys net charge. Beta decay appears to change charges, but it conserves them: a neutron (+0) converts to a proton (+1) plus an electron (−1) plus an antineutrino (0), and the ledger balances.

Why quarks carry thirds and leptons carry whole numbers

The fractional charges are not arbitrary. They fall out of how the strong force's gauge group, SU(3), assigns quarks to color triplets and how the electroweak group, SU(2) × U(1), assigns weak isospin and hypercharge. Charge is the combination Q = T₃ + Y, where T₃ is weak isospin and Y is hypercharge.

This is the mechanism most thin explainers skip. Charge is not a standalone property handed out at creation. It is a derived quantity from two more fundamental quantum numbers, and the allowed combinations are constrained by anomaly cancellation. For the theory to be mathematically consistent, the sum of charges across each generation must satisfy specific relations.

That constraint explains a counterintuitive fact: the up quark's +2/3 and the down quark's −1/3 are locked together. If you changed one, the proton would not be exactly +1, and atoms would not be neutral. The electron's −1 is likewise tied to the quark charges through anomaly cancellation. The whole scheme is over-determined by consistency, which is why physicists treat charge quantization as structural rather than coincidental.

Plain version: particle charges are not independent dials. They are a consistent package, and the package is fixed by the math of the Standard Model.

Quantified context: the numbers behind the charges

The elementary charge is defined as exactly 1.602176634 × 10⁻¹⁹ coulombs since the 2019 SI redefinition. That is a defined value, not a measured one, so it carries no uncertainty by construction.

Mass and charge do not track each other. The proton is about 1,836 times heavier than the electron but carries exactly opposite charge. The neutron is about 0.1 percent heavier than the proton despite carrying zero charge. The up quark's charge is +2/3, but its mass is only a few million electronvolts, while the top quark at +2/3 is roughly 173 GeV, about 10¹⁷ times heavier. Charge says nothing about mass.

The neutron's zero is not the same zero as the neutrino's. The neutron is a composite of charged quarks whose +2/3 and −1/3 contributions cancel exactly. The neutrino is elementary and carries zero charge by its own assignment. A neutron has an internal charge distribution, measurable through its magnetic moment; a neutrino does not.

For practical scale, one coulomb is about 6.24 × 10¹⁸ elementary charges. A typical lightning bolt transfers tens of coulombs, meaning roughly 10²⁰ electrons' worth of charge. The quantization is invisible at that scale but exact underneath.

The composite edge cases: where the simple story cracks

The clean table of charges works for free particles and simple bound states. It gets complicated in three places worth knowing.

First, hadrons. Protons and neutrons are the lightest baryons, but dozens of others exist. The Δ⁺⁺ baryon is three up quarks (+2), the Ω⁻ is three strange quarks (−1), and pions come in +1, 0, and −1 varieties. Charge still sums the constituents, but the constituent list changes.

Second, the neutron is not truly neutral internally. It has a nonzero charge radius and a magnetic moment, because its charged quarks are distributed unevenly. Experiments measuring the neutron's electric form factor find a small but nonzero charge distribution. The net charge is zero; the structure is not.

Third, virtual particles. In quantum field theory, a proton's charge is screened by a cloud of virtual quark-antiquark pairs. The bare charge and the screened charge differ, which is why charge runs with energy scale in quantum electrodynamics. The +1 you measure at atomic distances is the screened value.

A professional caveat here: the "charge" of a quark is also scale-dependent. The +2/3 is the value in a particular renormalization scheme at a particular energy. At very high energies the effective charge shifts. This is a real effect, not a rounding error, though it does not change the integer charges of bound states.

Common misconceptions, corrected

Several errors recur in thin explainers. Each is worth flagging directly.

Protons are not fundamental. They are composite, made of two ups and a down, and their +1 is a sum. Calling the proton "the positive particle" hides the quark structure. Neutrons are not "negative plus positive." They are one up and two downs. The arithmetic gives zero, but the internal arrangement matters for their magnetic behavior. Charge is not the same as mass or "amount of stuff." A heavy neutron has zero charge; a light electron has −1. There is no proportionality. Antimatter does not have "opposite mass." It has opposite charge and opposite quantum numbers, with identical mass. An antiproton has the same mass as a proton and charge −1. Quarks are never observed free. Confinement means you cannot isolate a +2/3 charge; you only see integer-charge hadrons. Any claim of a free fractional charge is a red flag. The electron's charge is not "the smallest possible." It is the smallest observed free charge, but quarks carry thirds. The unit e is a bookkeeping convention, not a floor.

One plain-language summary: charges are exact, additive, and conserved, but "neutral" does not mean "empty of charge" and "elementary" does not mean "simple."

Comparison: charge across particle families

The table's key lesson is that charge alone does not classify a particle. Two zeros (neutron and neutrino) arise from completely different physics.

Timeline: how the charge picture was assembled

The arc matters because it shows charge quantization was discovered empirically before it was explained theoretically. Millikan found the chunks; the Standard Model later explained why the chunks have the sizes they do.

Practical actions: how to use this correctly

If you are studying, teaching, or checking a claim about particle charge, these steps keep you accurate.

Sum the constituents before trusting a headline. Any composite particle's charge must equal its parts' charges. If a claimed particle's charge does not match its quark content, flag it. Distinguish "net charge" from "charge distribution." A neutral particle can have internal charge structure, as the neutron does. Treat fractional charges as confined. If a source claims a freely observed +2/3 charge, that is a red flag for error or hype. Use e as the unit and convert only when needed. The coulomb value is exact, so conversion introduces no uncertainty from the definition itself. Check the energy scale when reading precision charge measurements. Running of charge means the number depends on the scale probed. Do not confuse charge with mass, spin, or color. Each is a separate quantum number with separate conservation rules.

The threshold to remember: any isolated object's charge should be an integer multiple of e. Fractional values appear only inside confined composites, never as free particles.

Limits of the simple model

The Standard Model's charge assignments are extraordinarily well tested, but the framework has boundaries. It does not explain why the charges have the specific values they do; anomaly cancellation constrains them, but a deeper theory might derive them from something more fundamental. Grand unified theories often predict relations between quark and lepton charges, but none has been confirmed.

Charge quantization itself, the fact that every free particle's charge is an integer multiple of e, is observed but not fully explained within the Standard Model. Magnetic monopoles would explain it elegantly, but none has been detected. This remains an open question, and any claim that it is settled is overreach.

Finally, precision tests continue. The electron's charge is known to extraordinary accuracy through quantum Hall and Penning trap measurements, and any deviation from exact quantization would signal new physics. So far, none has appeared. The simple ledger of +1, 0, and −1 has held up under every test physics has thrown at it, which is itself a remarkable result.

For everyday purposes, the answer is stable and exact: protons +1, electrons −1, neutrons 0, up quarks +2/3, down quarks −1/3, neutrinos 0, and composites sum their parts. The depth lies not in the numbers but in why those numbers are locked together by the structure of the Standard Model.