Formula
protons=Z; neutrons=A−Z; electrons=Z−charge.
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Counts only; does not certify that a supplied isotope or charge state exists or is stable.
Example Calculation
Example inputs
- Atomic number Z: 6
- Mass number A: 12
- Signed ionic charge: 0
Carbon-12 with charge 0 has 6 protons, 6 neutrons and 6 electrons.
Frequently asked questions
How do I use this calculator?
Enter atomic number z, mass number a, signed ionic charge. The result updates automatically. Use Reset to restore the example values.
What method does it use?
protons=Z; neutrons=A−Z; electrons=Z−charge.. Counts only; does not certify that a supplied isotope or charge state exists or is stable.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.