def neutral_mass_from_mz_charge(mz: float, charge: int) -> float:
    """
    Calculate the neutral mass of an ion given its m/z and charge.

    Parameters
    ----------
    mz : float
        The ion's m/z.
    charge : int
        The ion's charge.

    Returns
    -------
    float
        The ion's neutral mass.
    """
    hydrogen_mass = 1.00794
    return (mz - hydrogen_mass) * charge