Evaluate an expression
Use parentheses to make the order explicit and choose degrees or radians before trigonometry. Results use floating-point arithmetic, so retain sufficient precision and independently check consequential calculations.
Calculators for expressions, graphs, dates and loan estimates
Start with the kind of answer you need: one number, a function plot, a calendar interval or a payment estimate. Each calculator runs in your browser and exposes its inputs so you can check the assumptions instead of trusting a number in isolation.
Choose by the job you need to do
Start with the task, then check the tool’s limits before relying on a result.
Inspect a function over an interval
Plot a function, adjust the visible range and trace values. A plotted line is a sampled numerical view, not a proof of continuity, roots or behavior outside the window.
Compare calendar dates
Calculate age or a date difference with the selected calendar dates. Calendar months have different lengths; an age in years and months is not interchangeable with a fixed number of days.
Explore a loan scenario
Compare the stated rate, amortization, market assumptions and optional extra payments. The estimate is not a lender quote and does not establish eligibility, fees or the cost of every mortgage product.
Check assumptions before using the answer
Record the expression or input values, units and selected options alongside the result. Change one input at a time when comparing scenarios. A copied number without its assumptions is hard to reproduce.
Use small cases with known answers as a check, then compare an independent method for consequential decisions. Calculators estimate from the supplied inputs; they do not verify a contract, prove a mathematical statement or replace professional judgment.
Worked examples and practical checks
Follow a complete example before applying the same workflow to your own files.
Worked example · 4 min read
Check an expression and graph before trusting a result
Verify calculator angle mode, parentheses and graph range with small reproducible examples. Learn why a numerical output or plotted line still needs context.