Photography tools that do the arithmetic

Depth of field, framing, exposure and astro planning — worked properly, with the assumptions written down instead of hidden. Your photographs never leave your device.

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Nothing is uploaded The calculators run on numbers you type. The file tools run on your own machine — images are read into the browser, worked on there, and never sent anywhere. Close the tab and nothing remains.

Planning & optics

The questions you want answered before you press the shutter, not after.

Depth of Field CalculatorNear and far limits, total depth, and the hyperfocal distance, drawn to scale with live sliders. Field of View CalculatorAngle of view for any format, how wide a scene that covers, and which lens fills the frame with a subject of known size. Panorama PlannerHow many frames a sweep needs at your overlap, including multi-row grids and the 360° wrap. Focus Stacking PlannerFocus positions that cover a range without gaps, spaced by the depth of field at each step. Macro CalculatorEffective aperture at magnification, the light it costs, and extension-tube magnification.

Exposure, astro & motion

Where the arithmetic is easy to get wrong and the shot is hard to repeat.

ND & Long Exposure CalculatorStack filters in stops, density or ND factor, and get a timer that survives the tab losing focus. Astrophotography Exposure PlannerThe 500 rule and the NPF rule side by side, with integration time and storage. Timelapse PlannerSolve for shoot duration, interval or final length — and catch an exposure that outruns its interval. Exposure ComparatorSolve the missing setting for an equivalent exposure, in real camera stops rather than rounded labels. Flash Guide Number CalculatorAperture, distance or required guide number, scaled for ISO, power fraction and modifier loss.

Image preparation

Sizing and cropping decisions, and the tools that already do the processing.

Print Size & Crop PlannerWhat resolution a print really needs at its viewing distance, and what a crop costs you. Resize ImagesBatch resize by edge, percentage or exact dimensions.Existing tool Compress to an Exact SizeBinary-searches quality to land under a target file size.Existing tool Contact SheetLay out thumbnails as a printable sheet.Existing tool Convert ImagesJPEG, PNG, WebP and AVIF, both directions.Existing tool HEIC to JPGUnpack what an iPhone gives you.Existing tool

Privacy

What your files say about you before you post them.

EXIF Viewer & RemoverSee what a photo carries — camera, timestamp, GPS — and download a stripped copy.Existing tool EXIF AnalyzerDrop a folder of photos and see how you actually shoot: focal lengths, apertures, ISO, lenses. PDF Metadata CleanerThe same idea for documents.Existing tool

Why these and not a hundred others

A photography calculator is only worth building if the answer depends on something the internet cannot know — your sensor, your lens, your subject distance, your print size, the files on your card. Anything you could settle with a single search does not need a tool, and most "photography calculator" sites are full of exactly that.

So the test each of these has to pass is simple: does it analyse your own files, simulate a decision you are about to make, or produce something you can act on? Depth of field passes because the answer moves with four inputs at once and the circle of confusion is a judgement you should be making deliberately. A page telling you what ISO stands for does not.

On fake precision

Optical formulas will happily return six decimal places for quantities that are approximations to begin with. Depth of field rests on a circle of confusion that encodes an assumption about viewing distance. Guide numbers are a manufacturer's best case. Raw file sizes vary with what is in the frame. The 500 rule is a darkroom-era heuristic.

Every tool here shows its formula and names what it cannot model — diffraction, pupil magnification, the tree at the edge of your frame. Where a figure is an estimate it is labelled as one, and where two published methods disagree, both are shown rather than one being picked quietly.

A note on the numbers engraved on your camera

f/11 is really f/11.314, and 1/250 of a second is really 1/256. The marked values are rounded, and a calculator that takes them literally will tell you that holding exposure from f/8 to f/11 needs 1/132 — arithmetically correct, and wrong to anyone who knows that is one stop. These tools convert marked values to their exact ones before doing stop arithmetic, then hand the answer back as a setting you can actually dial in.