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About this tool
Wrap share-card headlines with real Helvetica metrics, check they fit the safe area and stay legible at feed thumbnail size.
OG Image Text Fit Checker predicts where a share-card headline will wrap and how tall it renders once a feed shrinks the card, using published Helvetica advance widths (units per 1000 em) rather than a rough characters-per-line guess. It reports the widest line, the total text block height, the largest headline size that still fits your line limit, and whether the copy stays inside the region that survives every common centre-crop. Aimed at anyone writing or templating Open Graph cards who wants to catch a three-line overflow before it ships.
Open OG Image Text Fit Checker on AltFTool — it loads instantly in your browser.
Upload or drag in the file you want to work with.
Adjust the settings and preview the result.
Download the finished file to your device.
Uses real per-character advance widths instead of an average character count, so the line breaks match the render.
Converts your design-time font size into the pixel size a reader actually sees in the timeline.
Shows the intersection of the 1.91:1, 2:1, 1.5:1 and 1:1 centre-crops so nothing important gets cut.
1200 x 630 pixels is the standard, giving the 1.91:1 ratio Facebook, LinkedIn and most link unfurlers expect. X's summary_large_image card accepts the same file; keep it under about 5 MB and use PNG for text-heavy cards so type stays crisp.
Work backwards from the rendered size. A card designed at 1200 px wide is often shown around 300-550 px in a feed, so a 64 px headline lands at roughly 16-29 px on screen. Keep the headline at or above 12 px rendered, and target 16 px or more for comfort.
Different surfaces centre-crop the same file to different aspect ratios — 1.91:1, 2:1 and sometimes a 1:1 square thumbnail. On a 1200 x 630 card the square crop is only the middle 630 x 630 pixels, so anything outside that band can disappear.
It depends on the letters, not just the count: a capital W is 944 units per 1000 em in Helvetica while a lowercase l is 222, more than four times narrower. Measuring the actual string is the only reliable way, which is what this tool does.