Find the calculator you need.

Tip Calculator

Calculate a tip, the bill total, and an even per-person split from the bill amount and tip percentage.

Time Calculator

Find elapsed time between two clock readings, or add and subtract a duration from a clock time.

Speed Calculator

Enter any two of distance, time, and speed to solve the third.

Area Converter

Enter an area you already know, then choose the units to convert from and to.

Audiobook Time Calculator

Calculate audiobook listening time at a playback speed or the speed required for a target duration.

Book Reading Time Calculator

Estimate total book reading time from pages and personal pace, with an optional daily plan.

Business Days Calculator

Count eligible dates between two ordered dates, or move forward/backward by eligible workdays on an explicitly entered work calendar.

Clockout Calculator

Find a clock-out time from a daily target or the remaining paid hours in a period, including entered unpaid breaks.

Date Calculator

Add or subtract calendar time from a date, or find a signed calendar-day count between two dates with explicit endpoints.

Decimal Hours Calculator

Convert hours, minutes, and optional seconds to decimal hours or convert decimal hours back to duration components.

DOTS Calculator

Calculate explicitly named powerlifting points from bodyweight and a confirmed total or three entered lifts.

One Rep Max Calculator

Estimate a bench press, squat or deadlift maximum from one completed set, compare sourced equations, or calculate loads from a known maximum.

Plate Loading Calculator

Find the fewest balanced plates for an entered target and finite inventory, or total an entered per-side stack.

Reading Speed Calculator

Measure reading speed with a timed passage or calculate WPM from a known word count and elapsed time.

Reading Time Calculator

Estimate silent reading time from pasted text or a known word count at an editable reading speed.

Split Bill Calculator

Allocate one receipt, including entered tip and charges, into cent-reconciled equal shares or shares based on each person’s order.

Split Expenses Calculator

Reconcile who paid and who shares each expense, then show exact-cent reimbursements that clear the group’s balances.

Time Card Calculator

Build a one- or two-week time card with exact-minute totals, explicit overnight punches, and row-level validation.

Time Duration Calculator

Find the exact duration between two clock readings with an explicit same-day or next-day choice.

Week Number Calculator

Find the ISO week-year, week and weekday for a calendar date, or convert an ISO week date to its Gregorian date.

Wilks Calculator

Calculate explicitly named powerlifting points from bodyweight and a confirmed total or three entered lifts.

Work Hours Calculator

Total exact work minutes across a fixed week, subtracting only unpaid breaks you enter.

Workout Volume Calculator

Sum external load-volume and repetitions across entered workout rows without inferring training effect.

Concrete Calculator

Estimate net concrete volume, an order quantity with visible overage, and whole premix bags for common pour shapes.

Board Foot Calculator

Calculate board-foot volume and optional cost for milled lumber, or compare three named log-rule estimates in a separate mode.

Brick Calculator

Estimate bricks to order from wall face area, actual brick face dimensions, joints, openings and an entered allowance.

Concrete Block Calculator

Estimate CMU block count, mortar bags, sand, grout fill, and vertical reinforcement from wall dimensions, openings, block size, and waste allowance.

Concrete Mix Calculator

Scale a published 1:2:4 nominal-mix material schedule, or scale custom dry parts from a known cement volume.

Concrete Weight Calculator

Estimate the mass of a solid concrete volume using an explicit density and clear mass units.

Deck Board Spacing Calculator

Fit boards across a clear deck field, solve one even gap, or preserve the entered product gap with equal-width edge-board rips.

Decking Calculator

Estimate whole deck boards, lineal decking, and fasteners for a straight rectangular deck with every gap and allowance shown.

Drywall Calculator

Estimate whole drywall panels, covered area, joint tape, compound, and Type W screw weight from room dimensions or a known surface area.

Floor Joist Calculator

Estimate field-joist count, joists to buy, optional rim-board length, and total lineal feet without pretending to size the structure.

Flooring Calculator

Calculate planned packaged flooring, whole packages, leftover coverage, and optional material cost for one or more rooms.

Framing Calculator

Count wall studs and plate boards from wall length and chosen on-center spacing, with rough-opening and purchasing details kept optional.

Linear Feet Calculator

Convert a surface area to the running length of fixed-width material, with raw length kept separate from an optional order allowance.

Lumber Calculator

Turn a known same-size board count into whole boards to buy, board feet, lineal feet, and optional cost.

Lumber Weight Calculator

Estimate solid-lumber weight from actual dimensions or board feet, species density, quantity, and moisture content.

Mortar Calculator

Estimate whole premixed mortar bags from a masonry unit count or a supplier coverage rate.

Plywood Calculator

Estimate whole plywood sheets for a measured surface, or reverse sheets on hand into usable coverage.

Plywood Weight Calculator

Estimate per-sheet and stack weight from dimensions, thickness, and a named current industry-average density or custom density.

Rebar Calculator

Turn engineer-specified dimensions, cover, spacing, and bar size into bar counts, total length, theoretical stock-length equivalents, and approximate weight.

Square Footage Calculator

Find measured surface area from dimensions, including feet-and-inches entries and nonoverlapping sections.

Tile Calculator

Calculate tileable area, individual tiles, whole boxes, leftover coverage, and optional material cost for one or more surfaces.

Aspect Ratio Calculator

This aspect ratio calculator turns dimensions in one shared unit into a width-to-height ratio and calculates matching dimensions for resizing or fitting a frame.

Coefficient of Variation Calculator

Calculate sample or population relative spread, with signed CV and absolute percentage RSD.

Extended Euclidean Algorithm Calculator

Find integer coefficients x and y that reproduce the GCD of two signed integers, with complete coefficient rows and a modular inverse when it exists.

Factors Calculator

List every positive divisor and factor pair of a nonzero integer, with signed pairs for negative inputs.

Geometric Mean Calculator

Multiplicative mean with explicit nonnegative values, relative weights and equal-period changes.

Greatest Common Factor Calculator

Find the greatest divisor shared by two or more integers and inspect the Euclidean steps.

Harmonic Mean Calculator

Positive reciprocal means with relative weights and rate interpretation.

Interquartile Range Calculator

IQR, quartiles and outlier fences with explicit classroom and interpolated definitions.

Least Common Multiple Calculator

Find the least common multiple of two or more integers, with exact pairwise calculations.

Mean Absolute Deviation Calculator

Mean absolute distances from the mean or unscaled median distances from the median.

Mean Median Mode Calculator

Summarize the center and range of a numerical dataset without dropping outliers.

Percent Error Calculator

Compare one observed measurement with an entered nonzero accepted reference and distinguish absolute percent error from signed deviation.

Percentage Point Calculator

Find a signed arithmetic rate gap in percentage points or reconstruct a missing starting or ending percentage, with relative change clearly separated.

Pooled Standard Deviation Calculator

Combine within-group sample spreads with degrees-of-freedom weights.

Prime Factorization Calculator

Decompose an integer into prime powers and repeated prime factors, with division steps and a complete divisor check.

Ratio Calculator

This ratio calculator finds missing values, reduces ratios to whole-number terms, and scales or compares the values you enter.

Standard Deviation Calculator

Find sample or population standard deviation from raw observations, exact frequencies or grouped intervals.

Weighted Average Calculator

Combine numerical values with nonnegative weights and see each normalized contribution.

Z-Score Calculator

Standardize a value, reverse a score, or calculate explicitly labeled normal-model probabilities.

Percentage Calculator

Choose the percentage question you want to answer, then enter its two values. Percent change and percent difference remain separate choices.

GPA Calculator

Calculate a credit-weighted GPA from course grades and credit hours on a 4.0 scale.

Grade Calculator

Find your current course grade from weighted categories or total points, including known ungraded work and points-pool bonuses.

High School GPA Calculator

Calculate weighted and unweighted high-school GPA together from grades and course levels, with editable school-specific weights.

Cumulative GPA Calculator

Combine term or school GPAs into one cumulative GPA weighted by the credits behind each number.

Final Grade Calculator

Find a required final score or calculate the course grade after a specified final score.

GPA to Percentage Calculator

Convert a reported GPA to one proportional percentage estimate using the reported scale maximum.

Perimeter Calculator

Find the full boundary length of a common shape or a closed straight-sided polygon.

Quiz Grade Calculator

Turn correct or wrong answers into a quiz percentage, use points for partial credit, or find how many questions you can miss.

Semester Grade Calculator

Combine two marking-period grades and a final exam with the exact weights your school uses, or find the final score needed for a target semester grade.

Appliance Wattage Calculator

Estimate daily and yearly electricity use and operating cost for a household appliance from wattage, or from amps and volts when wattage is not listed.

Carpet Calculator

Calculate carpet coverage for rooms or straight stairs, with optional fixed-width broadloom planning, padding coverage, and material cost.

Paint Calculator

Estimate the paint volume for one interior room's walls, a ceiling, a whole exterior, or a primer coat, then see a rounded container-size planning example. Confirm which sizes the coating you choose is actually sold in.

Solar Panel Calculator

Estimate a home solar system size, panel count, roof area, annual generation, annual savings, installed cost, and simple payback period — or forecast yearly output from an existing array.

Wallpaper Calculator

Estimate whole wallpaper rolls from wall size, physical roll dimensions, match type, pattern repeat, and trim allowance.

Water Hardness Calculator

Enter any two of calcium, magnesium, and total hardness to solve the third. A total-hardness value by itself can also be converted and classified.

Gravel Calculator

Estimate cubic yards, short tons, and bags of crushed stone or gravel from the area and depth.

Mulch Calculator

Calculate cubic yards and whole bags of mulch from a bed's shape, dimensions, and depth.

Topsoil Calculator

Convert a measured lawn or garden area and soil depth into cubic yards, cubic feet, tons, and whole bags of topsoil.

Freight Linear Feet Calculator

Estimate trailer floor length from handling-unit count, footprint, and accepted stackability; mixed-size and density checks stay optional.