Free online tools and calculators
78 calculators, converters and generators for everyday tasks. Choose a tool and get started. No account needed.
Resistor color code calculatorRead a 4, 5 or 6 band resistor's value from its colors, or enter a resistance to find the matching bands.Ohm's law calculatorEnter two circuit values to calculate voltage, current, resistance and power, with units and formulas.LED series resistor calculatorCalculate an LED series resistor and its power dissipation from the supply voltage, forward voltage and current.Voltage divider calculatorFind the output voltage of a two-resistor divider, or solve for either resistor value.Parallel resistor calculatorCalculate total resistance for resistors in parallel or series. Add values and compare how current divides.Ceramic capacitor decoderDecode three-digit capacitor markings and show the capacitance in picofarads, nanofarads and microfarads.
JSON formatter and minifierValidate, format or minify JSON while preserving large numbers. Browse a source-aware tree, find keys and inspect duplicate-key warnings.Base64 encoder and decoderEncode text as Base64 or decode it back to text. Supports UTF-8 and URL-safe Base64.Image to Base64 converterConvert an image into a Base64 data URL, HTML image tag or CSS background. Preview it before copying the result.UUID generatorGenerate version 4 UUIDs individually or in batches. Inspect an existing UUID to check its version and structure.Unix timestamp converterConvert Unix timestamps in seconds or milliseconds to dates, or turn a date into a timestamp.Number base converterConvert integers between binary, octal, decimal and hexadecimal, with a view of the individual bits.
Design
Color, layout and CSS helpers
Color contrast checkerCheck the contrast ratio between two colors and see which WCAG text and interface thresholds they meet.Color converterConvert between HEX, RGB, HSL and HSV. Preview the color and copy values for CSS.CSS box shadow generatorAdjust offset, blur, spread and color with a live preview. Combine layers and copy the CSS.Aspect ratio calculatorFind an aspect ratio or calculate a missing width or height. Compare sizes for images, video and screens.Golden ratio calculatorDivide a length by the golden ratio, find related dimensions and preview the proportions.Lorem ipsum generatorGenerate placeholder words, sentences or paragraphs. Copy plain text or HTML for a layout.
Money
Loans, savings, tips and currency
Tip calculatorCalculate a tip, split the bill and see the total per person. Adjust the tip percentage and rounding.Mortgage payment calculatorEstimate fixed-rate mortgage payments and total interest. Include property tax, insurance and HOA fees if needed.Compound interest calculatorCalculate growth from an initial balance, regular contributions and a fixed interest rate. Compare compounding schedules.Currency converterConvert currencies with daily exchange-rate data. Check the rate date and compare several amounts.Discount and sales tax calculatorCalculate stacked discounts, user-entered tax and final totals with a receipt breakdown and rounding choices.Unit price comparisonCompare multipack prices at the same quantity and see the cheapest offer with savings against your baseline.
Case converterConvert text to sentence case, title case, uppercase, lowercase, camelCase, snake_case and other naming styles.Vowel counterCount vowels, consonants, words and characters as you type. Compare the frequency of each vowel.Prime number checkerCheck whether an integer is prime and find its factors. Supports large numbers and labels probable-prime results.Word and character counterCount words, visible characters, bytes and selected text. Estimate reading time at your chosen speed.Percentage calculatorCalculate a percentage, a proportion, percent change or an adjusted value with readable steps.Text cleanup and list organizerTrim, deduplicate, sort and reshape lists with an ordered recipe while keeping the original text available.
QR code generatorCreate QR codes for text, links, Wi-Fi and contact actions. Adjust colors and download PNG or SVG.BPM tapperTap along with a song to measure beats per minute. Compare half-time and double-time tempos.Sunrise and sunset mapChoose a location and date to calculate sunrise, sunset, twilight and day length on a world map.Tire pressure converterConvert tire pressure between PSI, bar and kPa. See all three units together.BMX gear calculatorCompare chainring and sprocket combinations, gear inches, rollout and speed at a given cadence.Bicycle chain length calculatorEstimate chain length from chainstay length and chainring sizes. See the length in inches and half-inch links.
Image compressorCompress JPEG, PNG or WebP images locally. Set maximum dimensions or a target size, compare the result and download the measured output.Image format converterConvert still images between JPEG, PNG and WebP. Choose a transparency background, quality and optional maximum width.Image metadata viewer and cleanerInspect camera, date, GPS, EXIF, IPTC and XMP tags in a local image. Create a cleaned copy and verify its exported metadata.PDF page organizerMerge, reorder, rotate, duplicate or extract PDF pages locally. Copy original page content and download a PDF or separate-page ZIP.Image resizer and cropperCrop, rotate, flip and resize JPEG, PNG or WebP images. Use ratio presets or exact coordinates and export from the original pixels.Images to PDFArrange local images into a PDF. Choose paper size, orientation, margins, fit or fill, resolution and image quality before exporting.
Concrete volume and bag estimatorAdd slabs, footings and round piers to estimate concrete volume, whole bags and material cost from your product yield.Brick and block estimatorSubtract wall openings, include mortar joints and estimate whole units and packs with a visible waste allowance.Roof pitch and rafter calculatorConvert roof pitch between rise/run, degrees and percent, and calculate common-rafter centerline and overhang geometry.Stair rise and run plannerCompare equal-riser layouts, choose the top landing and check tread dimensions against your entered constraints.Tile layout and cut plannerPreview a rectangular tile grid, compare centered layouts, inspect edge cuts and estimate whole boxes.Paint coverage and can estimatorMeasure rooms and openings, then estimate finish paint and primer cans using your coverage, coats and allowance.
