Free tools
Ecommerce tools built for founders.
Free calculators, image tools and generators for pricing, ad spend, social image sizes and product copy.
Calculators
16
Ecommerce Profit Margin Calculator
Calculate gross margin, net margin, profit per unit, and break-even ROAS for any ecommerce product.
Conversion Rate Calculator
Calculate your conversion rate, graded against the published market average, plus revenue per visitor.
Engagement Rate Calculator
Calculate an engagement rate for Instagram, TikTok, Facebook or X, graded against the published average for that platform.
TikTok Engagement Rate Calculator
Calculate your TikTok engagement rate by followers and by views, graded against the published average.
Facebook Engagement Rate Calculator
Calculate your Facebook engagement rate by fans and by reach, graded against the published average.
Twitter (X) Engagement Rate Calculator
Calculate your Twitter or X engagement rate by followers and by impressions, graded against the published average.
YouTube Engagement Rate Calculator
Calculate a YouTube engagement rate by views and by subscribers, with the interactions per 1,000 views and the comment share.
Instagram Engagement Rate Calculator
Calculate your Instagram engagement rate by followers and by reach, graded against the published all-industry median.
Image tools
13
Instagram Size Checker
Drop one image in and see what Instagram does to it in every format, with the crop drawn on your photo, then download the fixed file. Nothing is uploaded.
YouTube Thumbnail Size Checker
Drop a thumbnail in, see what YouTube does to it, and resize it to 1280 x 720, 4K or Shorts under the size limit. Nothing is uploaded.
Instagram Story Size Checker
See the 9:16 crop and the safe zones the profile row and reply box cover, drawn on your own story. Nothing is uploaded.
Facebook Cover Photo Size Checker
Facebook crops covers differently on desktop and mobile. See both crops and the area that survives them. Nothing is uploaded.
LinkedIn Banner Size Checker
See the 4:1 crop, the 15 percent mobile cut and where your profile photo lands on your banner. Nothing is uploaded.
YouTube Banner Size Checker
See the 2560 x 1440 crop and the 1235 x 338 safe area YouTube keeps on every device, drawn on your own banner. Nothing is uploaded.
Instagram Profile Picture Size Checker
Drop your photo in and see what the round crop hides. Instagram publishes no size, so every figure is labelled. Nothing is uploaded.
YouTube Thumbnail Downloader
Paste a YouTube link and download every thumbnail size YouTube stores, up to 1280 x 720. Nothing is uploaded.
Generators
12
AI Ad Generator
Paste your store URL and get finished static ads built from your customer reviews and from ads winning in your market.
AI Product Description Generator
Generate compelling product descriptions in multiple tones and lengths.
Creative Brief Generator
Turn a product, an audience and real customer language into a ten-section brief: one message, the insight behind it, deliverables and success metrics.
Brand Kit Generator
Read your brand kit off your own site: the colours in your CSS, the fonts you already use, and tone words evidenced by your own sentences.
Hook Generator
Turn your product and real customer reviews into ad, email, and landing page hooks, each labelled with the angle it uses.
AI Content Generator
The hub for the seven. One idea into posts, captions, carousels, scripts or a week of ideas.
Social Media Post Generator
One idea into three posts, each written for the platform you pick, with its angle named.
Instagram Caption Generator
Describe the photo and get five captions at the vibe, length and emoji level you choose.
Ad research
2
Ad Reporting Tool
Paste a Meta or TikTok export to spot winning creatives, ad fatigue, and budget leaks instantly.
Competitor Ad Finder
Enter one brand and open all four public ad libraries at the right place, with what each one will and will not show you.
All tools
Ecommerce Profit Margin Calculator
Calculate gross margin, net margin, profit per unit, and break-even ROAS for any ecommerce product.
Conversion Rate Calculator
Calculate your conversion rate, graded against the published market average, plus revenue per visitor.
Engagement Rate Calculator
Calculate an engagement rate for Instagram, TikTok, Facebook or X, graded against the published average for that platform.
TikTok Engagement Rate Calculator
Calculate your TikTok engagement rate by followers and by views, graded against the published average.
Facebook Engagement Rate Calculator
Calculate your Facebook engagement rate by fans and by reach, graded against the published average.
Twitter (X) Engagement Rate Calculator
Calculate your Twitter or X engagement rate by followers and by impressions, graded against the published average.
YouTube Engagement Rate Calculator
Calculate a YouTube engagement rate by views and by subscribers, with the interactions per 1,000 views and the comment share.
Instagram Engagement Rate Calculator
Calculate your Instagram engagement rate by followers and by reach, graded against the published all-industry median.
ROAS Calculator
Measure your return on ad spend, CPA, and CPC against industry benchmarks.
Break-Even ROAS Calculator
The ROAS at which your ads stop losing money, from your margin or your costs per order, plus your break-even CPA.
Customer Lifetime Value Calculator
Calculate CLV, monthly customer value, and your maximum acquisition cost.
CPM Calculator
Cost per thousand impressions, solved in any direction: fill any two of spend, impressions and CPM and the third is worked out.
CPC Calculator
Cost per click, plus the CTR and CPM the same three numbers already answer.
CTR Calculator
Click-through rate at two decimals, plus impressions per click and your click-to-conversion rate.
CPA Calculator
Cost per acquisition against the break-even CPA your order value and margin allow, so the number comes with a verdict.
CAC Calculator
Customer acquisition cost counting sales spend as well as marketing, plus the LTV to CAC ratio.
Instagram Size Checker
Drop one image in and see what Instagram does to it in every format, with the crop drawn on your photo, then download the fixed file. Nothing is uploaded.
YouTube Thumbnail Size Checker
Drop a thumbnail in, see what YouTube does to it, and resize it to 1280 x 720, 4K or Shorts under the size limit. Nothing is uploaded.
Instagram Story Size Checker
See the 9:16 crop and the safe zones the profile row and reply box cover, drawn on your own story. Nothing is uploaded.
Facebook Cover Photo Size Checker
Facebook crops covers differently on desktop and mobile. See both crops and the area that survives them. Nothing is uploaded.
LinkedIn Banner Size Checker
See the 4:1 crop, the 15 percent mobile cut and where your profile photo lands on your banner. Nothing is uploaded.
YouTube Banner Size Checker
See the 2560 x 1440 crop and the 1235 x 338 safe area YouTube keeps on every device, drawn on your own banner. Nothing is uploaded.
Instagram Profile Picture Size Checker
Drop your photo in and see what the round crop hides. Instagram publishes no size, so every figure is labelled. Nothing is uploaded.
YouTube Thumbnail Downloader
Paste a YouTube link and download every thumbnail size YouTube stores, up to 1280 x 720. Nothing is uploaded.
Social Media Image Sizes
Every surface in one table, each figure dated against the platform own page, with a checker per surface.
Instagram Grid Maker
Split one photo across your profile grid, numbered in the order you post them so the picture assembles the right way up. Nothing is uploaded.
Instagram Image Resizer
Free Instagram image resizer. Pick 1:1, 4:5, 3:4, 1.91:1 or 9:16, fit the whole photo or crop it, and download it at the exact size Instagram keeps.
Facebook Image Resizer
Free Facebook image resizer. Pick feed, square, link, story or cover, fit the whole photo or crop it, and download a JPG or PNG at the exact size. Nothing is uploaded.
X (Twitter) Image Resizer
Free X image resizer. Pick 16:9, square, 4:5 or header, fit the whole photo or crop it, and download a JPG or PNG under the 5 MB limit. Nothing is uploaded.
AI Ad Generator
Paste your store URL and get finished static ads built from your customer reviews and from ads winning in your market.
AI Product Description Generator
Generate compelling product descriptions in multiple tones and lengths.
Creative Brief Generator
Turn a product, an audience and real customer language into a ten-section brief: one message, the insight behind it, deliverables and success metrics.
Brand Kit Generator
Read your brand kit off your own site: the colours in your CSS, the fonts you already use, and tone words evidenced by your own sentences.
Hook Generator
Turn your product and real customer reviews into ad, email, and landing page hooks, each labelled with the angle it uses.
AI Content Generator
The hub for the seven. One idea into posts, captions, carousels, scripts or a week of ideas.
Social Media Post Generator
One idea into three posts, each written for the platform you pick, with its angle named.
Instagram Caption Generator
Describe the photo and get five captions at the vibe, length and emoji level you choose.
Instagram Carousel Generator
A topic into 5, 7 or 10 slides written in reading order, plus the caption to go under them.
Video Script Generator
A Reels, TikTok or Shorts script beat by beat: the line to say and the shot to film beside it.
LinkedIn Post Generator
One thing you know into three LinkedIn posts that read like a person, not a press release.
Content Idea Generator
Six post ideas for your account, each with its format, its opening line and why it would work.
Ad Reporting Tool
Paste a Meta or TikTok export to spot winning creatives, ad fatigue, and budget leaks instantly.
Competitor Ad Finder
Enter one brand and open all four public ad libraries at the right place, with what each one will and will not show you.
Want the ads, not just the numbers?
These tools give you a snapshot. Selzee is an AI ad generator: drop your website and get finished, on-brand static ads recreated from the ads winning on Meta right now, with new ones every day.
Get started for free