MailOptin vs uCalc
Compare WordPress plugins and tools side by side. Pick products with “Compare” in the software directory.
| Feature | MailOptin v1.2.78.7 · checked 23 Oct 2026 Free + paid · ★ 4.8/5 Visit Details | uCalc v2.0.1 · checked 23 Oct 2026 Free · ★ 3.3/5 Visit Details |
|---|---|---|
| At a glance | ||
| Active installs | 10,000+ | 600+ |
| Last updated | October 13, 2026 | August 25, 2023 |
| Editions | MailOptin Lite · MailOptin Premium ($) | uCalc |
| Pros | Popups, opt-in forms, notification bars and slide-ins; Blog posts sent as email newsletters; Connections to many email and CRM services; Shortcodes and a block for placing opt-in forms | Place a calculator with a shortcode, block or widget; Calculators are built in the uCalc service; Free plugin with no code needed |
| Cons | Premium themes and some features need the paid version; Many outbound connections to third-party services; Large codebase with many shortcodes and email templates | Needs a uCalc account and connection key; Calculators are hosted and edited in the uCalc service; Plugin was last tested with WordPress 6.3 |
| Mentioned in our posts | 1 | 1 |
| More features | ||
| Other features | Popups, opt-in forms and slide-ins, Opt-in form block, Email newsletter when a post is published, Email campaign builder, Scheduled email campaign sends, Premium optin themes ($) | uCalc shortcode to show a calculator, Gutenberg block for a calculator, Calculator widget, Connect a uCalc account with an API key, Pick a calculator from the account list, Editor button to insert a calculator |
| Integrations | ||
| Mailchimp, ConvertKit, MailerLite, Brevo | — | |
| CRM | HubSpot, Zoho CRM | — |
| Marketing | Klaviyo | — |
| E-commerce | WooCommerce | — |
| Plugins | WPForms, Contact Form 7, Gravity Forms | — |
| Other | — | uCalc service |
| Requires WordPress | 6.4 | 4.0 |
| Requires PHP | 7.4 | — |
| Tested up to | 7.1 | 6.3 |
| Phones home | No | No |
| External services | auth.mailoptin.io, challenges.cloudflare.com, www.google.com, vimeo.com, api.beehiiv.com, api.moosend.com, api.mailerlite.com, a.klaviyo.com, api.sendfox.com, clientapi.benchmarkemail.com, api.sendgrid.com, api.brevo.com, api.getresponse.com, api.convertkit.com, app.bentonow.com, api.sender.net, api.omnisend.com, api.encharge.io, api.egoiapp.com, api.ap3api.com, app.icontact.com, api.flodesk.com, api.sendpulse.com, api.getgist.com, api.mailgun.net, emailoctopus.com, api.elasticemail.com, api.getwemail.io, connect.mailerlite.com, api.ontraport.com, opencollective.com | ucalc.pro |
| Blocks | 2 | 1 |
| Shortcodes | 60 | 1 |