A toolkit of free utilities
Beyond paychecks, Sri Murugan Systems keeps a family of 55 free online tools. Each one is fast, works in your browser and needs no sign-up. Save the ones you use.
- No sign-up
- Works in your browser
- Free to use
Energy, solar and power
- ProSolarCalcSolar sizing, payback, battery and incentive calculators.prosolarcalc.com
- Solar Battery Bank CalculatorSize a battery bank for a solar or off-grid system.solarbatterybankcalc.com
- Backup Power CalculatorBattery or generator runtime for your loads.backuppowercalc.com
- Voltage Drop CalculatorSize wiring from the voltage drop over a cable run.voltdropcalc.com
- AC Tonnage CalculatorSize air-conditioning tonnage for a room or building.actonnagecalc.com
- Utility Rate CalculatorUS electricity bills by utility, from each utility's own tariff.utilityratecalc.com
- EB Bill CalculatorIndian electricity bills for every state, from official tariffs.ebbillcalc.com
Money and business
- EMI CalculatorLoan EMI and the full amortisation schedule.indiaemi.com
- SIP CalculatorMutual fund SIP returns and maturity value.sipcalculatorhub.com
- Total Interest CalculatorThe total interest paid over a loan.totalinterestcalc.com
- Margin vs MarkupConvert margin and markup, with break-even.marginvsmarkup.com
- Percentage CalculatorPercentages, percent change and tip splits.bestpercentagecalculator.net
Home and construction
- Square Footage CalculatorArea in square feet from dimensions.thesquarefootagecalculator.com
- Cubic Yardage CalculatorCubic yards of concrete, mulch, gravel and soil.cubicyardage.com
- Concrete CalculatorConcrete volume and bags for slabs and footings.concretematerialcalc.com
- Roofing CalculatorShingles, underlayment and roofing materials.roofingmaterialcalc.com
- Stair CalculatorStair rise, run and stringer sizes.staircalculators.net
- Construction CalculatorEstimators for common construction materials.constructioncalchq.com
- Pool Volume CalculatorPool water volume in gallons or litres.poolvolumecalc.com
- Tank Volume CalculatorTank volume and fill level.tankvolumecalc.com
- Box Volume CalculatorBox volume from length, width and height.boxvolumecalculator.com
Shipping
Health and kitchen
Study, numbers and time
- Fraction CalculatorAdd, subtract and simplify fractions, with steps.fractionsteps.com
- GPA CalculatorGPA and CGPA from grades and credits.gpacalculatorhq.com
- Number to WordsNumbers written out in words.numtotext.com
- Age CalculatorExact age from a date of birth.theagecalculator.net
- Unit Cheat SheetEngineering unit converter with reference tables.unitcheatsheet.com
- Calculate HoursWork hours, timesheets and overtime.calculatehours.net
- Clock With UsAlarm clock, timer, stopwatch and world clock.clockwithus.com
Developer tools
- Base64 DecoderDecode Base64, JWTs and certificates in the browser.base64decode.tools
- URL Encode/DecodePercent-encoded text to and from plain text.urlencodedecode.com
- UUID CoreGenerate, validate and convert UUIDs.www.uuidcore.com
- JSON ToolsFormat, validate, minify and convert JSON.jsontools.tools
- Hash GeneratorMD5, SHA and other hashes for text or files.hashgenerator.tools
- Epoch TimeUnix timestamps to dates and back.epochtime.tools
- Crontab SheetExplain and build cron expressions.crontabsheet.com
- Regex GuideExplain, test and build regular expressions.regexguide.com
- CIDR CalculatorIPv4 and IPv6 ranges and subnet boundaries.cidrcalculator.net
- Subnet Mask CalculatorSubnet masks, host bits and address ranges.subnetmaskcalc.net
Text, images and files
- Word CounterWords, characters, sentences and reading time.wordcounterfree.com
- Text RepeatRepeat words or emoji with separators.textrepeat.net
- Transform CaseTitle, sentence and programming cases.transformcase.com
- PicToolkitCompress, convert, resize and crop images locally.pictoolkit.com
- Remove MetadataStrip EXIF, GPS and hidden metadata.removemetadata.tools
- PDF ToolsMerge, split, compress and convert PDFs in the browser.corepdftools.com
- Color Code KitHEX, RGB and HSL colours and palettes.colorcodekit.com
- Barcode and QRQR codes and barcodes from text or data.barcodeandqr.com
- Password StrengthTest a password and make a stronger one.passwordstrength.net