GPA calculations
Calculate course GPA, combine terms, or estimate a target using your own school scale and credit rules.
Academic arithmetic
GPA Calculator
Calculate credit-weighted, unweighted, or weighted GPA with an editable grade scale.
Academic arithmetic
Cumulative GPA Calculator
Combine an existing GPA with a new term or estimate the future GPA needed for a target.
Everyday commerce calculations
Calculate tips, discounts, margin, and markup from values you supply without pricing, accounting, tax, or tipping recommendations.
Everyday commerce
Tip calculator
Calculate a tip, total bill, and equal per-person split from a custom percentage.
Everyday commerce
Discount calculator
Calculate percent off, savings, and final sale price or reverse-calculate the discount.
Everyday commerce
Margin calculator
Calculate profit margin or solve a selling price for a target margin.
Everyday commerce
Markup calculator
Calculate cost-based markup or solve a selling price for a target markup.
Fractions, factors, and number notation
Use exact rational, integer, Roman-numeral, and scientific-notation tools without creating one page for every possible input value.
Exact math & notation
Decimal to fraction calculator
Convert exact terminating decimals to simplified fractions and mixed numbers.
Exact math & notation
Fraction to decimal calculator
Convert fractions and mixed numbers to terminating or repeating decimals.
Exact math & notation
Roman numeral converter
Convert conventional Roman numerals and integers in both directions.
Exact math & notation
GCF calculator
Find the GCF, GCD, or HCF of two or more integers with exact arithmetic.
Exact math & notation
Scientific notation calculator
Convert, add, subtract, multiply, and divide scientific-notation values.
Date and time calculations
Add calendar units, measure one clock interval, compare complete date-time values, or count customizable working days without hidden timezone or holiday assumptions.
Date & time
Date Calculator
Add or subtract days, weeks, months, and years from a calendar date with explicit month-end clamping and no timezone drift.
Date & time
Hours Calculator
Calculate hours and minutes between two clock times, including overnight intervals and an optional break deduction.
Date & time
Time Duration Calculator
Calculate elapsed days, hours, minutes, and seconds between two complete civil date-and-time values without hidden timezone conversion.
Date & time
Business Days Calculator
Count business days between dates or add and subtract working days with customizable weekdays and excluded dates.
Grades, dates, math, data, and science
Use these focused utilities for weighted grades, integer and algebra work, date intervals, statistics, charts, chemistry, percentages, division, and ratios.
Math foundation
Square Root Calculator
Calculate principal real square roots with exact perfect-square and simplified-radical output.
Math foundation
Fraction Simplifier
Reduce signed integer fractions to lowest terms with exact BigInt arithmetic.
Math foundation
Exponent Calculator
Calculate exact supported integer powers and approximate real powers with explicit domain boundaries.
Math foundation
Factorial Calculator
Calculate exact factorials for nonnegative integers through 5,000.
Physics and coordinate math
Speed Calculator
Solve for speed, distance, or time with explicit physical units.
Physics and coordinate math
Density Calculator
Solve for density, mass, or volume with correct cubic conversions.
Physics and coordinate math
Midpoint Calculator
Find the midpoint between two 2D or 3D coordinate points.
Physics and coordinate math
Distance Formula Calculator
Find Euclidean distance between two 2D or 3D coordinate points.
Measurement and geometry
Square Footage Calculator
Calculate square feet across one or more rectangular sections with explicit mixed units.
Measurement and geometry
Volume Calculator
Calculate volume for five common three-dimensional shapes with correct cubic conversions.
Measurement and geometry
Area Calculator
Calculate general geometric area for six common shapes with squared-unit conversions.
Measurement and geometry
Circumference Calculator
Calculate circle circumference from radius or diameter.
Percentage calculator
Percentage Calculator
Solve the three fundamental percentage relationships for a part, rate, or whole.
Percentage calculator
Percentage Difference Calculator
Compare two values symmetrically using their average absolute magnitude.
Percentage calculator
Percentage Increase Calculator
Measure an increase or increase a number by a selected percentage.
Percentage calculator
Percentage Change Calculator
Calculate signed directional change from an original value to a new value.
Focused math utility
Proportion Calculator
Solve exactly one missing value in a proportion with cross-multiplication steps and undefined-case validation.
Focused math utility
Slope Calculator
Calculate slope from two points and identify vertical, horizontal, and identical-point cases.
Focused math utility
Aspect Ratio Calculator
Simplify a width-to-height ratio and calculate a matching new dimension.
Focused math utility
Weighted Average Calculator
Calculate a weighted average from values and nonnegative numeric or percentage weights.
School & grades
Final grade calculator
Calculate the final exam score needed for a target course grade or the resulting course grade from a known exam score.
Math & geometry
LCM calculator
Find the least common multiple of two or more integers with prime-factor steps, validation, and zero handling.
Math & geometry
System of equations calculator
Solve a two-variable linear system, identify unique, no, or infinite solutions, and review elimination and determinant steps.
Statistics & data
Pie chart maker
Create an accessible local SVG pie chart from category labels and values, with percentages, a legend, and a text table.
Time & dates
Days between dates calculator
Calculate elapsed days and weeks between two calendar dates with optional inclusive counting and leap-year handling.
Math & geometry
Percentage decrease calculator
Calculate absolute and percentage decrease from an original and new value, with clear increase and zero-original handling.
Math & geometry
Long division calculator
Divide integers with quotient, remainder, decimal result, and accessible digit-by-digit long-division working steps.
Statistics & data
Mean calculator
Calculate arithmetic mean, sum, count, median, mode, and range from a numeric dataset with clear steps.
Science
Molarity calculator
Calculate molarity, moles of solute, or solution volume using M = moles per liter with liter and milliliter conversion.
Math & geometry
Ratio calculator
Simplify a two-part ratio with decimal, zero, and sign validation and a clear common-factor step.
Work, time, statistics, and math
Use these tools for time cards, clock conversion, advertising ratios, strength estimates, statistics, algebra, dates, and geometry.
Work, time & math
Time card calculator
Add daily clock-in and clock-out times, subtract unpaid breaks, and calculate weekly regular, overtime, and decimal work hours.
Work, time & math
CPM calculator
Calculate advertising CPM, total cost, or impressions by entering any two known values, with formula steps and input validation.
Work, time & math
Military time converter
Convert 12-hour time to military time or 24-hour time back to AM/PM, including midnight, noon, leading zeros, and a complete chart.
Work, time & math
One rep max calculator
Estimate one-repetition maximum from weight and repetitions using Brzycki and Epley formulas, with a visible range and clear limitations.
Work, time & math
Right triangle calculator
Solve a right triangle from two valid known values and calculate missing sides, acute angles, area, perimeter, and hypotenuse.
Work, time & math
Standard deviation calculator
Calculate sample or population standard deviation, variance, mean, count, and calculation steps from an entered numeric dataset.
Work, time & math
Pythagorean theorem calculator
Find a missing right-triangle side from any two known sides using a² + b² = c², with validation and substitution steps.
Work, time & math
Quadratic formula calculator
Solve ax² + bx + c = 0 with the quadratic formula, discriminant, real or complex roots, validation, and substitution steps.
Work, time & math
Chronological age calculator
Calculate exact chronological age in calendar years, months, and days between a birth date and comparison or test date.
Work, time & math
Cylinder volume calculator
Calculate cylinder volume from radius or diameter and height, with selectable units and cubic-unit, liter, and gallon conversions.
Construction and material planning
Use a specialized calculator when material density, pool shape, stair geometry, or a particular project volume matters.
Construction & material
Asphalt calculator
Estimate asphalt area, volume, cubic yards, and tonnage from project dimensions, thickness, density, and waste allowance.
Construction & material
Cubic yard calculator
Calculate cubic yards from length, width, and depth using mixed imperial or metric units, with cubic feet, cubic meters, and waste-adjusted results.
Construction & material
Cubic feet calculator
Calculate cubic feet from mixed-unit length, width, and height or depth, with cubic-yard and cubic-meter conversions.
Construction & material
Gravel calculator
Estimate gravel volume and optional tonnage from dimensions or area, depth, waste, supplier density, and user-entered price.
Construction & material
Topsoil calculator
Estimate topsoil cubic feet, cubic yards, and cubic meters from area and depth, with optional settling allowance and user-entered bag volume.
Construction & material
Stone calculator
Estimate stone or rock volume and optional tonnage from area, depth, allowance, and an editable supplier bulk density.
Construction & material
Concrete slab calculator
Estimate concrete slab volume in cubic feet, cubic yards, and cubic meters from length, width, thickness, and optional waste allowance.
Construction & material
Stair calculator
Estimate basic stair geometry from total rise, planning riser target, tread depth, and available run, without claiming code compliance.
Construction & material
Pool volume calculator
Estimate rectangular, circular, or oval pool volume in US gallons, liters, cubic feet, and cubic meters using average depth.
Construction & material
Landscape material calculator
Plan gravel, topsoil, stone, or mulch volume from area and depth, with optional supplier density, waste, and user-entered unit pricing.
Shared accuracy controls
- Inputs are validated before calculation.
- Formulas and worked examples stay visible.
- Conversions use deterministic factors.
- Displayed rounding does not change the underlying calculation.
Privacy and boundaries
- Calculator inputs remain in the browser.
- Analytics records only safe tool actions after consent.
- Each result states its important assumptions.
- Policy, legal, medical, and professional decisions require separate verification.
These tools provide calculation aids and planning estimates, not bids, engineering specifications, financial advice, legal conclusions, medical advice, supplier guarantees, or code approvals.