Free Calculators, Formulas You Can Check
No sign-up, no clutter — just the number you came for, calculated from a sourced formula and verified by hand before it went live.
Popular Right Now
One Rep Max (1RM) Calculator
Estimate the heaviest weight you could lift for a single rep, based on a set you've already done.
Coast FIRE Calculator
Find out if your current savings alone could grow into full financial independence by retirement age.
IVF Due Date Calculator
Estimate your due date and key pregnancy milestones from your embryo transfer date.
FFMI Calculator
Work out your normalized Fat-Free Mass Index and see how your muscularity compares to natural and enhanced lifters.
Car Loan Payoff Calculator
See how many months and how much interest you'll save by putting extra money toward your auto loan each month.
Car Depreciation Calculator
Estimate how much your car's value will drop over the next few years.
Debt Snowball Calculator
Enter each debt and see exactly how many months to debt-free, and how much interest you'll pay, with the debt snowball method.
PTO Accrual Calculator
Project your paid time off balance at a future pay period, based on your current balance and accrual rate.
Browse by Category
Health & Fitness
Strength, cardio, and nutrition numbers.
Finance
FIRE planning, debt payoff, investing, and real estate.
Pregnancy & Baby
Due date estimates for fertility treatment timelines.
Home & DIY
Sizing, cost, and payback math for house and yard projects.
Food & Nutrition
Ratio math for baking and brewing.
Crafts & Making
Exact quantities for wax, resin, and fiber art projects.
Sports & Hobbies
Scoring systems and gear math for lanes and the range.
Games
Scoring rules and build math for tabletop, card, and dice games.
Auto
Depreciation and loan payoff for car ownership.
Productivity & Work
Time off balances and true employee cost.
Beauty & Personal Care
Skin, sun exposure, and personal care questions.
Electronics & Making
Firmware and build math for 3D printing, CNC, and electronics projects.
Pet Care
Practical numbers for raising, breeding, and caring for pets.
Why TrueCalc
Most calculator sites optimize for ad space, not accuracy. We do the opposite: every formula on this site is traced back to a named source — a published study, an official standard, or a well-documented convention — checked by hand against a known example, and tested in a real browser before it's published. No account, no email gate, no walls of ads between you and your answer. See exactly how we do it on our accuracy page.