Compare API costs across 20+ models including GPT-4, Claude, and Gemini side by side.

Calculate monthly payments, total interest, and get a full amortization schedule instantly.

Calculate your BMR, TDEE, and daily macro targets for weight loss, maintenance, or muscle gain.

Estimate your true take-home pay after federal, state, FICA taxes and pre-tax deductions like 401(k).

Calculate the hourly rate you need to charge to cover taxes, expenses, and hit your income goals.

Calculate the exact late fee to add to an overdue invoice using flat fee, monthly percentage, or daily interest.

Estimate your SE tax, federal income tax, state tax, and quarterly payments for 2026.

See which pays more after taxes, benefits, SE tax, QBI deduction, and break-even rate.

Enter your loan amount, interest rate, term, and expected revenue to calculate ROI and net profit.

Analyze any rental deal — cash flow, cap rate, NOI, cash-on-cash return, DSCR, and 5-year projections.

Calculate profit margin, markup, and selling price in one tool, and see why a 50% markup is only a 33% margin.

Calculate how much you could save in taxes by electing S-Corp status, including break-even profit level.

Estimate your one-rep max using the Epley formula and get training weights for every intensity zone.

Calculate your daily protein, carbohydrate, and fat targets based on your calorie goal.

Estimate body fat with the U.S. Navy method or a BMI-based estimate, plus lean mass and your healthy range.

Work out what to send the IRS each quarter, when it is due, and which safe harbor keeps you clear of the underpayment penalty.

Compare the simplified and regular IRS methods side by side, with depreciation and the income limit, and see which one leaves you better off.

Project what regular contributions grow into, set the compounding and contribution frequencies separately, and see what the balance is worth after inflation.

Compare the 2026 contribution limits for both plans on the same net profit, see the split behind the Solo 401(k) number, and find out which one gives you more room.

Work out how many units, or how much revenue, you need to cover your costs, without needing to know your contribution margin first.

Work out the cap rate on a rental property from the price, rent, vacancy and running costs, and see the most you could pay to hit a target.