Everyday Calculators

Calculate calendar age and the number of days until the next birthday.

Count calendar days between two dates or add and subtract days from a date.

Add or subtract seconds from a duration and convert the result to decimal hours.

Calculate net clock-time hours between a start and end, subtracting a break.

Convert length, weight, temperature, volume and speed using explicit unit definitions.

Calculate a tip and split the bill evenly across a group.

Estimate fuel quantity and trip cost using metric consumption or US fuel economy.

Calculate a credit-weighted average from grade points on a 0–4 scale.

Combine percentage scores and weights while distinguishing partial work from final grades.

Estimate concrete volume for a rectangular slab with an optional ordering allowance.

Estimate whole tiles from surface area, tile size and a cutting allowance.

Estimate liters of paint from area, coats and the product’s coverage rate.

Estimate energy and usage cost from average watts and operating hours.

Convert distance and elapsed time into average speed in three unit systems.

Measure fuel economy from distance traveled and fuel consumed.

Find a Gregorian date’s weekday, day number within its year and leap-year status.

Count Monday–Friday days, excluding the holiday dates you supply.

Estimate input, cached-input and output token charges for an entered request volume.

Model proportional request charges and a fixed plan charge without assuming a provider.

Relate average throughput, response time and in-flight requests using Little’s Law.

Translate a time-based availability percentage into allowed downtime over an entered period.

Estimate a declared set of full backups and daily incrementals after compression.

Estimate retention storage across cameras from an encoded bitrate and schedule.

Estimate uncompressed audio payload from sample rate, bit depth, channels and duration.

Convert pixel dimensions to a physical print size at an entered pixel density.

Estimate physical pixel density from active-screen resolution and diagonal size.

Find the largest crop matching a target ratio and the amount removed from each side.

Estimate constant-load runtime from nominal battery energy and an entered usable fraction.

Estimate energy from panel power, peak-sun hours and a retained-output assumption.

Estimate charging time from battery charge change, average input power and efficiency.

Compare annual electricity and gasoline costs for the same traveled distance.

Estimate rainfall collection and empty-tank overflow from a roof catchment.

Translate an entered watering depth and application efficiency into run time.

Calculate ideal replacement volume needed to reach an entered dissolved-concentration target.

Estimate ideal thermal energy and heating time before environmental losses.

Scale a named ingredient list to a different number of servings while preserving its units.

Include a starter’s flour and water when calculating dough hydration and salt percentage.