Update of 7 October 2026: Helios photo editor and ten unit converters

Helios is a free photo editor that you open in your browser like any other web page. It opens JPG, PNG, HEIC, WebP, AVIF, TIFF, GIF and BMP photos as well as camera RAW files, including CR3, CR2, NEF, ARW, RAF, ORF, RW2 and DNG. There is nothing to install and no account to create, saving is always free, and your photos never leave your device. You will find it on the Helios page, which also explains every button step by step, and in the new Advanced category.

What you can do in Helios:

• You fix the light and colour in the Light, Color, Color mixer, Detail, Color grading and Effects sections, and the Light and Color sections each have an Auto button.
• The eyedropper removes a colour cast when you click something in the photo that is actually white or grey.
• Crop mode has the Free, Original, 1:1, 4:5, 3:2 and 16:9 aspect ratios, straightens a photo by up to 45° and has an Auto straighten button.
• The histogram, Show clipping, the Original button and a Before and after view with a movable divider show what your edits change.
• Zoom goes up to 800%, and from 100% you see the real pixels of the photo.
• The History panel takes you back to any step.
• You can choose from 100 filters in twelve categories, set Filter strength from 0 to 150% and save your own looks in the My filters category.
• Apply settings to selected copies your settings to a whole set of photos, with the option Match brightness and white balance to this photo.
• The Save photos window has Full quality, Website and email, Social media and Custom settings, and it saves to JPG, PNG, WebP, AVIF, TIFF, BMP and GIF, with several photos at once in one ZIP file.
• Keep camera data (without location) keeps the camera details in the new file, while the GPS location and serial numbers are always removed.
• Your work is saved in the browser, and the Continue editing button brings it back. Download settings and Load settings save your edits to a file and open them again.

Helios also handles the cases that usually go wrong. HEIC files open in Safari 16.4 and later, and in Chrome and Edge when your system has an HEVC decoder; in a browser without one, such as Firefox, the editor tells you where the file will open. If a ready-made filter would blow out part of the photo, the editor moves the Whites slider to the left, and the Exposure slider too if needed, only as far as necessary. Ads only appear in a separate column along the right edge of the editor, or in a narrow strip at the very bottom on phones and other small screens, so they never cover the photo or the buttons.

Helios also replaces the simple image editor. The old editor’s address now opens Helios in your language, or the English version in Arabic, where Helios is not available yet. You crop a photo in Crop mode and set its size in pixels in the Save photos window.

Every subcategory with unit converters now has a converter on the subcategory page itself, in all eight languages. You type a value, choose the unit to convert from and the unit to convert to, and the result appears straight away. The title of each page says how many units it knows:

• The length unit converter has 302 units: metric, imperial and US, nautical and astronomical units, old units from Poland, Russia, the German-speaking countries, the Czech lands, Scandinavia, France, Spain, Portugal and Italy, Japanese and Chinese units, and ancient and Biblical measures.
• The weight unit converter has 150 units, including jewellers’ carats, troy and apothecaries’ units, old national units and Biblical weights.
• The volume unit converter has 260 units, including the cooking measures of each market, barrels and bottles, old national units and Biblical measures.
• The pressure unit converter has 53 units, from the microbar to the megabar, with atmospheres, columns of mercury and water, psi and the pieze.
• The speed unit converter has 33 units, including Mach, the speed of light, running, swimming and rowing pace and rain intensity in mm/h and in/h. Under the result it shows the Beaufort force, counted from the WMO limits in metres per second.
• The data unit converter, which was already on the site, grew from 25 to 43 units, with every bit and byte unit up to the quettabyte from the SI prefixes adopted in 2022, the binary units up to the quebibyte and the nibble.
• The data transfer rate converter has 62 units: bits and bytes per second up to exabits, amounts per minute, hour, day, week and month, and 26 named links such as T1, E1, ISDN, USB, Thunderbolt and Ethernet, each with its nominal speed.
• The color converter has 37 notations, including HEX, RGB, HSL, HSV, CMYK, Lab, LCH and OKLCH, the CSS colour spaces Adobe RGB, ProPhoto RGB and Rec. 2020, YCbCr for video and JPEG, CIE XYZ, xyY and Luv, and colour code for Android, Swift, Flutter and RGB565 displays.
• The pixel and DPI converter has 16 units for screen and print, with a resolution field in DPI, px/cm or dppx.
• The typographic unit converter has 18 units, including DTP and American points, several variants of the Didot point, the cicero, the Japanese Q, em and rem.

The fields read what people type. You can write the unit after the number in the language of the page, for example “20 Greek fathoms”, “5 long tons” or “4 E1”, and the list switches to that unit. In Polish and Czech the fields understand every grammatical form after a number, such as “1,5 cetnara” or “5 krychlových metrů”. A unit of another quantity, such as square feet in the length converter, gives a message instead of a result, and an entry such as “1.500”, which means different numbers in different countries, comes with a line saying how it was read.

Now that every subcategory has its own unit converter, a separate page for every pair of units in every language is no longer needed. We checked which pairs people actually search for in each language and removed 673 pages for pairs that get very little traffic there, such as Pbps to Tbps in every language except English. In English we also removed some data size and transfer speed pages, such as MB/s to MiB/s. The number of tools now differs from one language to another, with the most in English and Spanish and the fewest in Czech.

A pair of units is always kept or removed in both directions. If you need one of the removed pairs, the converter on the subcategory page, for example the data unit converter or the volume unit converter, converts it in the same way. Pages that were already on the site before the 30 September update now open that subcategory page instead. In German, the CSV, JSON, XML, YAML, Markdown and HTML converters now open their English versions, because the German file format subcategory no longer has any tools.

• The data size field used to turn a word it did not know into a number without a warning, so “2 apples” gave 2 MB. It now shows a message and leaves the result empty, both in the data unit converter and on the data size converter pages, such as the MB to GB converter.
• French names with accents, such as “1 téraoctet” and “1 pétaoctet”, and the spelling “kilo-octet” were read as the wrong unit. They now give the right one.
• In the transfer speed fields, “2 T1” was read as 2 Tbit/s. It now means two T1 lines, which is 3.088 Mbit/s.
• When you type a unit letter by letter, for example “2 kilobytes”, the field no longer turns your entry into a number halfway through the word.
• The number of tools next to each category and subcategory on the home page now includes the converter on the subcategory page, so these numbers add up to the total at the top of the page.

The data unit converter has a new table that shows how many photos fit in 1 GB and how long you can listen to music or watch films with it, with a source for every file size.

French pages now have a non-breaking space before colons, semicolons, question marks and exclamation marks and inside « » guillemets, as French typography requires, so these signs never move to the start of a new line on their own. The same applies to messages under the converter fields.