The number of allowances you claim on Form W-4 affects the amount of federal income tax withheld from your wages. Claiming 0 allowances generally results in the highest amount of tax being withheld, as it assumes no personal exemptions or adjustments to income. Claiming 1 allowance reduces the amount of tax withheld, as it considers the taxpayer's personal exemption. The more allowances you claim, the less tax is withheld from your wages. However, it is important to note that the number of allowances you claim should accurately reflect your tax situation to avoid under- or over-withholding. Claiming too many allowances may result in owing taxes at the end of the year, while claiming too few allowances may result in a larger refund but reduced take-home pay throughout the year. It is advisable to review the instructions on Form W-4 or consult with a tax professional to determine the appropriate number of allowances to claim based on your specific circumstances.