US calculators

Full PITI payment, PMI, amortization schedule and extra-payment savings.

Growth chart, regular contributions, compounding frequency and inflation-adjusted real value.

Per-state sales-tax engine, trade-in tax credit, negative equity and 2026 rates by credit score.

Payment, total interest, amortization with CSV export, and an extra-payment payoff savings mode.

Preset percentages, per-person bill splitting and round-up, with US tipping norms.

Employer-match modeling, today's-dollars projection, growth chart and 2026 IRS limits.

Official CPI-U series 1913–2026: equivalent dollar value, cumulative and annualized inflation, chart.

Average effective rate by state for 2026, homestead exemptions, monthly escrow and your state's median bill.

Project savings to a future value, or set a goal and find the monthly amount needed, with a growth chart.

Lump sum plus monthly or yearly contributions, inflation-adjusted real value, two-scenario compare and a downloadable schedule.

Melt value of gold, silver and platinum by weight, karat and editable spot price, with dealer payout % and price per gram by karat.

Income snapshot, a year-by-year DRIP reinvestment projection, and real 2026 qualified dividend tax brackets plus the 3.8% NIIT by filing status.

Months to payoff and total interest at your APR, including the minimum-payment trap and extra-payment scenarios.

Tax-free growth with 2026 IRS contribution limits and MAGI phase-outs, versus a taxable account.

Your 2026 after-tax 401(k) capacity under the $72,000 415(c) limit, with the $8,000 catch-up and the $11,250 super catch-up for ages 60-63.

Defined-benefit pension from multiplier × service years × final average salary, with early-retirement reductions and a lump sum vs annuity comparison.

Maximum home price from your income and debts under the 28/36 rule, with FHA 31/43 and aggressive presets, PMI and a full PITI breakdown.

Move-in and move-out rent, with the actual-days, 30-day and 365-day methods compared side by side.

Texas protest kit: personalized appeal letter, uniform deadlines, evidence checklist and ARB hearing playbook ($49 PDF).

2026 federal brackets with a per-bracket breakdown, marginal vs effective rate and filing-status comparison.

Salary or hourly take-home pay after federal, FICA and state tax, with a full per-paycheck breakdown.

Auto-fills the 2026 rate by state, reverses tax from a total, and splits state vs local.

Annual, monthly, weekly and hourly pay converted both ways, with unpaid-vacation adjustments.

Free Excel and CSV pay stub template with earnings, FICA deductions and net-pay formulas prebuilt.

Five modes on one page with the working shown for your exact numbers — no Calculate button.

Weighted and unweighted GPA side by side on the 4.0 scale, with unlimited courses.

Add, subtract, multiply or divide fractions with the steps shown and the answer simplified.

Weighted course grade and letter, plus the exact grade you need on the final to reach your target.

Round to any place from millions to millionths, significant figures or the nearest 0.25 — 9 rounding modes explained, exact decimal maths (0.145 rounds to 0.15) and a number line.

Total, lateral and base surface area for 11 shapes — sphere, cylinder, cone, pyramid, prism and more — with the working shown, open/closed variants and honest error bounds.

Mean, median, mode, range, geometric mean and standard deviation from any pasted list — with the working shown for every statistic, plus a weighted average mode.

Volume of cubes, prisms, cylinders, spheres, cones, pyramids and capsules in metric or imperial units.

Solve any triangle from SSS, SAS, ASA, AAS or SSA — sides, angles, area, perimeter and heights, ambiguous case included.

Sale price from percent off or amount off, stacked discounts done right, and optional sales tax.

Gross margin, markup and the difference between them — solve for price, cost or margin in any direction.

Standard score from x, mean and SD, converted to percentiles and left/right/between probabilities.

CI for a mean or proportion at 90/95/99 percent, using z or Student t for small samples.

Population and sample standard deviation, variance and mean with the full step-by-step formula.

Rise over run to percent grade, degrees and ratio, two-point slope with the line equation, and ADA ramp checks.

Convert between 4.0, 4.3, 5.0 weighted scales, percentages and letter grades.

Quotient and remainder with the full long-division layout worked digit by digit — bring down, multiply, subtract at every step, decimals optional.

Simplify ratios with Euclid's GCD shown step by step, solve A:B = C:x proportions, scale to a total, and convert ratio to fraction and percent.

Counts sig figs citing the exact rule applied to each zero, rounds to n significant figures digit-exact, and applies the multiplication and addition rules.

Roots of ax²+bx+c with the discriminant, simplified radicals, complex roots as a±bi, vertex and factored form — every algebra step written out.

Integer factors, prime factorisation, GCF and LCM, plus trinomial factoring by the AC method with difference-of-squares and perfect-square detection.

Hypotenuse or missing leg in exact simplified-radical and decimal form, Pythagorean-triple check, and the triangle's area and perimeter.

Add, multiply, transpose and invert matrices up to 4×4, with cofactor-expansion determinants and Gauss-Jordan steps shown row by row.

Eigenvalues and eigenvectors for 2×2 and 3×3 matrices with the characteristic polynomial derived step by step and trace/determinant checks.

P(X=k), cumulative and range probabilities with the formula substituted in full, a distribution table, and the normal approximation when valid — exact to n=1000.

Symbolic derivatives of elementary single-variable functions to third order, naming the rule applied at every node — power, product, quotient, chain, trig, exp and log.

Balances chemical equations by exact-fraction Gaussian elimination on the stoichiometric matrix, with per-element atom counts and a final verification.

Visual WHO gauge, your healthy weight range in lb and kg, and how far you are from it.

BMR and daily calories via Mifflin-St Jeor, goal-based targets and a macro breakdown.

US Navy method with ACE category gauge, plus fat and lean mass in lb and kg.

Devine, Robinson, Miller and Hamwi in lb and kg, the Peterson equation, and your healthy BMI range.

Steps to miles and km — personalised from your height and pace (Barreira 2010, ACSM), or an honest range across the three common conventions, plus what research actually says about 10,000 steps.

Your 1RM as an honest range across all 7 published formulas (Epley, Brzycki and more, per LeSuer 1997), with the NSCA %1RM training-load table in lb and kg.

Estimated due date from LMP (Naegele rule), conception date or IVF transfer, with trimester milestones.

A 63-day canine gestation timeline from mating or ovulation, week by week.

Human-age equivalent using the 2020 epigenetic formula and size-adjusted veterinary tables, versus the old times-7 rule.

Pace, speed and finish time across 5K to marathon, a Riegel race predictor and a full pace chart.

Room-by-room builder that totals any shapes, with waste factor, material cost and ft²/yd²/m²/acres.

Slabs, footings, walls and columns in cubic yards, 40/60/80 lb bag counts, 10% overage and cost — multi-element total.

Footprint and pitch to true roof area, roofing squares and shingle bundles, with live slope factor, waste, material cost and a roof diagram.

Volume in cubic feet from any mix of inches, feet, yards, cm and metres — boxes, cylinders and area×height, multi-item totals, cost and exact cu yd/m³/litre/gallon conversions.

Cubic yards and tons of gravel, crushed stone, pea gravel or sand from area and depth, with cost estimate.

Square footage across multiple rooms, waste factor by install pattern, boxes needed and total cost.

DC, single-phase and three-phase AC conversions with power factor and common US voltages.

NEC-based drop for copper or aluminum by AWG size, with the 3 percent branch-circuit recommendation check.

Wattage and hours of use to kWh and monthly cost, preloaded with the latest EIA average residential rate.

Cubic yards for rectangular, circular and triangular areas, with truckloads, bag counts and material weight from real density tables.

Exact years, months and days, age in every unit, birth weekday and next-birthday countdown.

Weekly time card with break deduction, overnight shifts, automatic overtime and pay.

Days, weeks, months and years between two dates at once, with true business days and an exact breakdown.

Add or subtract years, months, weeks and days — or business days — from a date, with the result weekday, 30/60/90 presets and .ics export.

Exact duration between two times or datetimes, decimal hours, overnight spans and duration math.

US, UK, EU and CM (Mondopoint) shoe sizes for men, women and kids, including youth-to-women conversion.

Band and bust measurements to US and UK bra sizes, with sister sizes and the UK cup divergence beyond D explained.

Circumference or diameter in mm to US, UK letter and EU (ISO 8653) ring sizes, with a string-and-ruler method.

Waist measurements to US women's jeans sizes (00-24), EU sizes and the reality of vanity sizing.

15 to 120-second typing test on real sentences: gross and net WPM, accuracy and a consistency score, using the standard 5-character word.