All tools

Block quantity calculator

How many concrete blocks you need for a wall from its area.

Brick quantity calculator

How many bricks you need for a wall, with a reverse mode for a fixed brick count.

Includes reverse mode

Concrete bag calculator

Convert a concrete volume into the number of pre-mixed bags to buy.

Concrete volume calculator

How much concrete you need for a slab, footing or base, with a reverse mode.

Includes reverse mode

Flooring quantity calculator

How many packs of laminate, engineered or vinyl flooring to buy for a room.

Insulation calculator

How many rolls of loft or wall insulation you need for an area.

Paint coverage calculator

How many litres of paint to buy for a wall, ceiling or room.

Patio slab calculator

How many paving slabs you need for a patio, with an allowance for edge cuts.

Plaster/plasterboard estimator

Plasterboard sheets and skim plaster needed to board and finish a wall or ceiling.

Roof pitch calculator

A roof's pitch in degrees and as a ratio, from its rise and run.

Screed calculator

Volume of sand-cement screed needed for a floor, plus an approximate bag count.

Tile quantity calculator

How many tiles to buy for a floor or wall, with a cutting-waste allowance.

Baking-pan area converter

Work out a rectangular baking pan's area and the equivalent round tin diameter.

Cake-tin size converter

Find the square cake tin size with the same baking area as a round tin.

Cups to grams by ingredient

Convert a US cup measurement to grams for common baking ingredients.

Gas mark converter

Convert a UK gas mark oven setting to Celsius and Fahrenheit.

Grams to cups by ingredient

Convert a gram weight to US cups for common baking ingredients.

ml to cups converter

Convert millilitres to US cups.

Ounces to grams converter

Convert ounces to grams for cooking and baking.

Oven temperature converter

Convert an oven temperature between Celsius and Fahrenheit.

Recipe scaler

Scale a recipe to a different number of servings, with a reverse mode for a fixed ingredient amount.

Includes reverse mode

Serving-size calculator

How much each serving gets from a total amount and the number of servings.

Tablespoons/teaspoons converter

Convert between tablespoons and teaspoons.

Date String Portability Checker

Checks whether a date/time string is unambiguous and portable across runtimes.

.env Portability Preflight

Finds .env values that behave differently across Node/Docker/shell/Python.

Regex Portability Checker

Checks whether a regular expression will work the same way in another language or engine.

SQL Identifier Portability Checker

Checks a table/column name against reserved words and quoting rules across databases.

URL Parser Differential Checker

Shows how different URL parsers interpret unusual or ambiguous URLs.

Package Version Format Translator

Translates and checks compatibility between version-string formats (SemVer, PEP 440, and more).

YAML Cross-Runtime Preflight

Checks whether YAML will behave consistently across CI, Docker Compose, Kubernetes and more.

YAML Semantic Difference Checker

Shows how the same YAML means something different under YAML 1.1 vs YAML 1.2 rules.

Annual mileage cost

Turns a per-mile running cost into a yearly and monthly budget figure.

Battery energy to range reverse estimator

How far you can go from the battery energy you have left.

Includes reverse mode

Diesel journey cost

The fuel cost of a diesel journey, from distance, fuel economy and pump price.

EV charging cost calculator

What an EV charge will cost, from battery size, charge range and electricity price.

Includes reverse mode

EV charging time calculator

How long an EV charge will take, from battery size, charge range and charger power.

EV cost per mile

Your EV's running cost per mile, from its efficiency and electricity price.

EV vs petrol running-cost comparison

Compares the running cost of covering the same distance by EV versus petrol.

Miles to km converter

Converts a distance between miles and kilometres.

MPG to L/100km converter

Converts UK mpg fuel economy figures to litres-per-100km.

Petrol journey cost

The fuel cost of a petrol journey, from distance, fuel economy and pump price.

Air-conditioner cost calculator

How much it costs to run a portable or window air-conditioning unit.

Appliance running-cost calculator

How much it costs to run any electrical appliance from its power rating and usage.

Battery runtime calculator

Estimates how long a battery will power a device from its capacity and the device's power draw.

Dehumidifier running-cost calculator

How much it costs to run a dehumidifier.

Dishwasher cost calculator

How much it costs to run a dishwasher per cycle and per year.

Electric-heater cost calculator

How much it costs to run an electric heater from its power rating and usage.

kWh cost calculator

Turns a known kWh usage figure into a cost using your electricity price.

LED lighting cost calculator

How much it costs to run a set of LED bulbs from their wattage, count and daily use.

Tumble-dryer cost calculator

How much it costs to run a tumble dryer per cycle and per year.

Washing-machine cost calculator

How much it costs to run a washing machine per cycle and per year.

Watts to kWh calculator

Converts a power rating and run time into energy used in kWh.

Cake servings calculator

Looks up how many party servings a round cake gives, by diameter.

Catering portions estimator

Estimates total food weight to cater, accounting for plated vs buffet style.

Chair quantity calculator

Works out how many chairs to hire or set out for an event.

Event-duration planner

Adds up an event's total running time from its planned activities.

Food portions estimator

Works out roughly how much food to prepare or order for an event.

Ice quantity estimator

Works out how much ice to order for an event.

Invitation-count planner

Works out how many invitations to send to reach a target guest count.

Pizza quantity estimator

Works out how many pizzas to order for a party.

Room-capacity estimator

Estimates how many guests a room can hold for a given layout style.

Includes reverse mode

Table quantity calculator

Works out how many tables you need to seat your guests, with a reverse mode.

Includes reverse mode

EML/MIME Import Doctor

Checks a raw .eml (RFC 822 / MIME) email file for constructs that behave differently across mail clients and importers.

Markdown Portability Preflight

Checks Markdown source for constructs that render differently across GitHub-Flavored Markdown, strict CommonMark and stripped-down renderers.

MIME Attachment Filename Doctor

Checks attachment filenames declared inside a raw .eml/MIME message for portability problems when saved to disk across Windows, macOS and Linux.

Text File Portability Preflight

Checks a plain text file for encoding/line-ending/whitespace issues that cause it to behave differently across operating systems, editors and tools.

Compost calculator

How much compost you need to mulch or improve a bed or border.

Decking calculator

How many deck boards you need for a deck area.

Fence panel calculator

How many fence panels and posts you need for a fence run.

Grass seed calculator

How much grass seed you need to sow or overseed a lawn.

Gravel calculator

How much gravel you need for a path or driveway, in tonnes and bags.

Hedge plant calculator

How many hedging plants you need for a single-row hedge.

Mulch calculator

How much bark or wood-chip mulch you need for a bed, with a reverse mode for a fixed bag count.

Includes reverse mode

Plant-spacing calculator

How many bedding plants fit into a bed on a regular grid.

Pond volume calculator

Estimates a pond's water volume from its length, width and average depth.

Raised-bed soil calculator

How much soil mix you need to fill a raised bed, with a reverse mode for a fixed amount of mix.

Includes reverse mode

Topsoil calculator

How much topsoil you need for a bed, border or levelling job, in cubic metres and bags.

Turf calculator

How many turf rolls you need to lay a new lawn.

Extension rough-cost estimator

A very rough single-storey extension budget from the floor area and a cost rate.

Flooring budget estimator

Full supply-and-fit budget for new flooring — materials and labour.

Heating-energy estimator

The electricity cost of running a heater, from its power rating and daily usage.

Home maintenance budget planner

A rough annual home-maintenance budget as a percentage of property value.

Loft conversion budget estimator

A rough loft conversion budget by conversion type — rooflight, dormer or hip-to-gable.

Moving-cost planner

A rough budget for a house move by property size, distance and packing option.

Painting budget estimator

Full supply-and-fit budget for painting a room — materials and a decorator's labour.

Renovation budget estimator

A rough renovation budget from the area being worked on and a cost-per-square-metre rate.

Solar payback estimator (with explicit assumptions)

Roughly how many years a home solar PV system takes to pay for itself.

Aspect-ratio calculator

Works out the simplified aspect ratio from any width and height.

DPI calculator

Works out the DPI an image will print at, from its pixel width and print size.

Image-resize dimensions

Works out the correct height for a resized image to keep its proportions.

Paper-size converter

Looks up standard paper size dimensions in mm and inches.

Photo print-size calculator

Works out the pixel dimensions needed to print cleanly at a target photo size.

Pixels to centimetres

Converts a pixel measurement to centimetres at a given resolution.

Pixels to inches

Converts a pixel measurement to inches at a given resolution.

Poster-dimension helper

Works out the largest poster size from an image at a minimum quality.

PPI calculator

Works out an image's pixel density (PPI) at a given print or display diagonal.

Print-size calculator

Works out the largest size you can print an image at a chosen quality.

Screen-dimension calculator

Works out a screen's actual width and height from its diagonal and aspect ratio.

Audio file-size estimator

Estimates an audio file's size from its bitrate and duration.

Bitrate calculator

Works out the bitrate needed to hit a target file size for a given duration.

Data-usage calculator

Projects daily data usage forward to a weekly and monthly total.

Download-time calculator

Estimates how long a download will take from the file size and connection speed.

File-transfer-time calculator

Estimates how long a local file transfer (USB, drive-to-drive) will take.

GB/MB/TB converter

Converts a data amount between megabytes, gigabytes and terabytes.

Mbps to MB/s converter

Converts a connection speed from megabits to megabytes per second.

Screen PPI calculator

Works out a screen's pixel density (PPI) from its resolution and diagonal size.

Upload-time calculator

Estimates how long an upload will take from the file size and upload speed.

Video file-size estimator

Estimates a video file's size from its bitrate and duration.

Add/subtract days

Adds or subtracts a number of days from a date.

Break-time calculator

Adds up how much time daily work breaks total over a week and a year.

Business days between dates

Works out how many working days (Mon–Fri) are between two dates.

Countdown calculator

Counts down the days remaining until a target date.

Days between dates

Works out exactly how many days are between two dates.

Hours between times

Works out the number of hours between two times of day, including overnight spans.

Meeting overlap helper

Finds the overlapping time window between two people's availability.

Months between dates

Works out how many complete calendar months are between two dates.

Shift-length calculator

Works out the paid length of a work shift, minus an unpaid break.

Weeks between dates

Works out how many weeks are between two dates.

Working-hours calculator

Works out total working hours per week and per year from daily hours and holiday allowance.