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Calculators, converters and file tools that explain their work. No accounts. No uploads where your browser can do the job.

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▧Image compressorCompress locally. Download instantly. PDFMerge PDFsPrivate, in-browser processing %Percentages20% of 80 = 16

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Compress images Compress JPG, PNG or WebP images locally in your browser. Merge PDFs Combine multiple PDF documents in the order you choose. Percentages Calculate a percentage of a number, percentage change, or percentage difference with the formula shown. Date difference Find the signed number of days, weeks and calendar span between two dates. Convert units Convert common metric and imperial units with full precision and readable results. Create a QR code Generate a downloadable QR code for a URL or short text. Count words Count words, characters, sentences, paragraphs and estimated reading time as you type. Format JSON Validate, format and minify JSON locally with clear parse-error messages. Open whiteboard Sketch ideas, map flows and arrange notes on a private infinite canvas with optional browser-only autosave and portable backups. Build UTM links Build a properly encoded campaign URL with source, medium, campaign and optional UTM parameters. Margin & markup Convert between cost, selling price, profit, gross margin and markup without confusing the two percentages. Journey fuel cost Estimate fuel used and journey cost from distance, consumption and fuel price. Heat pump cost Estimate heat-pump electricity use and compare running cost with gas, oil or another fuel. EV charging cost Calculate energy drawn from the grid and the cost of charging an electric car between two charge levels. 3D print cost Estimate filament, electricity, hands-on labour and failed-print allowance for an FDM part. CNC cycle time Estimate machining cycle and total batch time from cutting length, feed, rapids, tool changes and setup. Concrete volume Calculate concrete volume for a rectangular slab and add a practical waste allowance and bag estimate. Electricity cost Calculate the daily and annual electricity use and running cost of an appliance, machine or group of devices. Battery payback Estimate annual bill savings and simple payback for a home battery using your usable capacity, cycling, tariffs and efficiency. Radiator output Estimate a radiator’s output at heat-pump flow and return temperatures, then compare it with a room heat-loss requirement. CNC speeds & feeds Calculate spindle speed, table feed, feed per revolution and cutting time from metric tool data. Laser cutting cost Estimate laser cutting time, machine cost, labour, production cost and a selling price at your target gross margin. Laser pulse overlap Calculate pulse spacing, pulses per millimetre, scan overlap, hatch overlap, pulse energy and approximate peak power for pulsed laser marking. Metal FFF shrinkage Calculate metal FFF green-part dimensions and separate X/Y and Z slicer scale factors from expected or measured sintering shrinkage. DMX address planner Plan repeated DMX fixture addresses, footprints and universe rollover, then read a nine-switch DIP pattern or copy a compact patch sheet. Material weight Calculate the weight of common stock shapes from dimensions, material density and quantity. Dimensional weight Compare a parcel’s volumetric weight with its actual weight using the carrier divisor you choose. Convert image formats Convert PNG, JPEG and WebP images locally without uploading the original, creating an account or adding a watermark. Resize images Resize a PNG, JPEG or WebP image to exact pixel dimensions while preserving its aspect ratio when requested. Organize PDF pages Extract, reorder and rotate PDF pages locally by entering the page order you want in the downloaded document. View e-invoice XML Turn a UBL or UN/CEFACT CII electronic-invoice XML file into a readable summary without sending it to a server. Solar after saldering Estimate how ending the Dutch salderingsregeling changes the annual value of your solar electricity using your own consumption and contract rates. Article 50 checker Identify which Article 50 transparency situations may apply to an AI system or AI-generated content and produce a review checklist. Generate AI disclosures Create a concise, accessible disclosure for AI-generated or AI-assisted text, images, audio or video. Solar self-consumption Compare current and target solar self-consumption, grid imports, exports and the estimated annual value of shifting electricity use into sunny hours. Break-even point Calculate contribution per unit, break-even sales volume and the units needed to reach a target profit. Business days Count business days between dates or add and subtract working days with custom weekend days and holidays. Crop images Crop PNG, JPEG and WebP images by pixels or a centred aspect-ratio preset, preview the selected area and download the result locally. Pallet layout Estimate cases per layer and per pallet using pallet dimensions, case size, loaded-height and weight limits, with an illustrated mixed-orientation pattern.

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Our practical guides explain the file formats, formulas and assumptions behind selected tools—using worked examples and primary technical sources.

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Lighting control · 8 min

DMX addressing explained: fixture footprints, universes and DIP switches

Plan DMX start addresses without overlaps, understand fixture footprints and universe rollover, and decode common nine-switch binary addresses.

Read guide Manufacturing · 7 min

Metal FFF sintering shrinkage: calculate the correct green-part scale

Why shrinkage percentage cannot simply be added to 100%, how to calculate inverse scale and why X/Y and Z should be measured separately.

Read guide Laser marking · 8 min

Laser pulse overlap explained: spacing, hatch and pulse energy

Calculate pulse spacing and geometric overlap from scan speed, frequency and spot size, then keep hatch spacing and pulse energy distinct.

Read guide

Useful answers,without the clutter.