Calculators Tools
Free calculators for percentages, loans, dates, grades, and everyday math.
Five percent modes with live results: percent of, change, add, and subtract.
Split a bill and tip evenly with presets, live totals, and a copyable summary.
Exact age in years, months, and days with a birthday countdown and copyable summary.
Find the exact span between two dates with live results and a copyable summary.
Calculate BMI with your preferred weight and height units, see your category on a visual scale, and copy a summary.
Calculate semester GPA or cumulative CGPA in one place. Switch tabs to use preset or custom grading scales, per-course grade points, credit-weighted semester averages, a visual scale, grading reference, and copyable or downloadable reports.
Calculate monthly loan payments (EMI), total interest, and a yearly amortization breakdown.
Find the sale price and how much you save after a percentage discount, with optional stacked discount and sales tax.
See how savings grow with compound interest, regular contributions, and adjustable compounding frequency.
Solve for voltage, current, resistance, or power: enter any two values and get the rest instantly, with the formula shown.
Look up diameter, cross-sectional area, resistance per length, and copper ampacity for any AWG wire gauge, in copper or aluminum.
Calculate voltage drop over a wire run by gauge, length, current, and system voltage, and find the minimum gauge that stays under 3%.
Find the socket size for a metric or SAE bolt, or the bolt size for a measured nut, with a size chart and fit-checked substitutes.
Find the correct tap drill size for metric, UNC, or UNF threads at any percentage of thread engagement.
Find the hex key for metric or inch cap, button, flat, and set screws, or see which screws a key fits, with a full size chart.
Convert number, letter, fractional, and metric drill sizes, or find the nearest drills to any size, with a full drill chart.
Find the clearance hole and drill for metric (ISO 273) and inch bolts in every fit, plus counterbores for socket head cap screws.
Handiwork’s calculators take the guesswork out of everyday numbers. Work out a percentage, estimate a loan payment, project compound interest, split a bill, or count the days between two dates: each calculator shows clear results instantly as you type.
They are handy for students, shoppers, travelers, and anyone managing money or deadlines. Pick a calculator below; there is nothing to download and nothing to sign up for.