TIFF is lossless, alpha, and several images inside a single file. PNG is lossless compression with a full 8-bit alpha channel. ImageMagick sits between the two, and this page says exactly what happens to a TIFF file on the way to becoming a PNG one.
What runs when a TIFF file becomes PNG
ImageMagick 6.9.12, on a machine we rent and watch. Your TIFF file is uploaded once, ImageMagick runs once, the PNG comes back, and neither file is kept. TIFF to PNG is one of the 3649 pairs that engine was probed on with a real file, which is why it has a page here and why the pairs the probe could not prove do not.
What survives from the TIFF into the PNG
The pixel dimensions of your TIFF file. The PNG comes out the size the TIFF went in, because nothing on this path resizes anything.
Transparency. TIFF and PNG both carry a real alpha channel, so a cut-out sent as TIFF is still a cut-out as PNG.
Every pixel value. TIFF and PNG are both lossless, so the PNG file adds no compression artefacts that the TIFF did not already have.
What TIFF to PNG costs you
Every page of the TIFF but the first. A TIFF file can hold several images in one container; a PNG file holds exactly one.
If a model is going to read the PNG
A PNG file is pixels, and pixels are expensive for a model to read. Handed this PNG, an assistant spends its budget looking at the picture rather than reading it, and it will paraphrase what it thinks it saw. If your TIFF is mostly words, the useful move is to pull the text out of it, not to change which picture format holds it.
TIFF to PNG, measured rather than promised
Running TIFF to PNG against the real engine with a real file, ImageMagick wrote 815 bytes of PNG in under a tenth of a second, machine otherwise idle. That is one TIFF file on one day and not an average, which is why the number is given together with the file that produced it.
The TIFF to PNG verdict was reached by a format signature, meaning at least four bytes unique to the format were found at the right offset. Which check was used matters, because they do not all prove the same thing, and a status code of 200 proves nothing whatsoever about whether the PNG file has anything inside it.
The same TIFF file, sent somewhere else
Other outputs the probe measured out of a TIFF file, so the cost of choosing PNG can be read against something. Sizes do not compare across engines, because each family was probed with its own TIFF witness file.
TIFF to PDF: 118,721 bytes in under a tenth of a second, verified by a format signature.
TIFF to JPG: 1,568 bytes in under a tenth of a second, verified by a format signature.
TIFF to WEBP: 370 bytes in under a tenth of a second, verified by a format signature.
TIFF to GIF: 3,512 bytes in 0.1 seconds, verified by a format signature.
Other ways into PNG, and what they measured
Among the published routes into PNG, TIFF is the ninth largest output of the 13 measured. The witness files differ, so this ranks the probe run and not your document.
PDF to PNG: 1,294 bytes in 0.1 seconds.
AVIF to PNG: 4,453 bytes in under a tenth of a second.
PSD to PNG: 689 bytes in under a tenth of a second.
ICO to PNG: 810 bytes in under a tenth of a second.
HEIF to PNG: 1,403 bytes in under a tenth of a second.
What we will not pretend about TIFF to PNG
A TIFF file over 25 MB is refused before the upload finishes rather than after it, so you do not wait for a rejection.
A TIFF to PNG run that passes 30 seconds is killed, and the ImageMagick process is killed with it. A run left behind would sit on one of the machine's two cores until somebody noticed.
No text is read out of the TIFF anywhere on this path. Converting a picture to PNG never turns it into words, whatever the picture happens to contain.
ImageMagick was not saturated at sixteen simultaneous conversions: it held 47.5 a second while latency moved from 0.22 s to 0.34 s, and the service memory did not move off 51 MB. That is the measured headroom behind TIFF to PNG, not a marketing number.
One TIFF file at a time, chosen in the browser. There is nothing else to set up and nothing else on offer.
TIFF to PNG: what people ask
What actually converts my TIFF file to PNG?
ImageMagick does it, 6.9.12, on a machine we rent and watch. Not a browser trick and not somebody else service: the TIFF file is uploaded once, ImageMagick runs once, the PNG comes back, and neither file is kept afterwards.
How long does TIFF to PNG take?
On the file the probe used, ImageMagick took under a tenth of a second and wrote 815 bytes of PNG. That is one real measurement on one real TIFF file, not an average and not a promise about yours: a larger TIFF takes longer, and past 30 seconds the run is stopped.
What do I lose going from TIFF to PNG?
The one to know about first: Every page of the TIFF but the first. A TIFF file can hold several images in one container; a PNG file holds exactly one.
My TIFF holds more than one image. Which one comes back?
The first. A TIFF file can carry several images in one container and a PNG file carries exactly one, so the engine takes the first rather than inventing a way to give you the rest.
Is TIFF to PNG free?
There is a free allowance every month, and one TIFF to PNG conversion costs half a credit against it. When the allowance runs out the tool says so and stops, rather than quietly handing you a worse PNG.