How to send SMS from your computer: free with your phone or in bulk for your business

To send SMS from your computer you have two options: connect your phone to your PC or Mac, which is free, or use an SMS platform in your browser, which is the right choice when you’re texting many customers at once. Both let you use the keyboard and the big screen, but they’re meant for different things.

If you just want to reply to messages without picking up your phone, the tools that already come with Android, Windows and macOS are all you need. If you run a business and want to tell your customer list about an offer, an appointment or an order, you need something else. This guide walks you through both cases step by step.

What you need to send SMS from your computer

A computer doesn’t have a SIM card, so it can’t send an SMS on its own. Something else always sends it on its behalf.

In the first case, that something is your own phone. The computer just acts as a screen and keyboard: you type on your PC, the message travels to your phone and goes out from your number, at your carrier’s rates.

In the second case, it’s sent by an SMS platform. You log in to its website, upload the numbers and the message goes out over the carrier network with your company name as the sender. You pay for each message.

Before you choose, answer one question: are you going to write to one person or to a hundred? The answer decides almost everything.

3 free ways to send SMS from your computer with your phone

These options cost nothing beyond your mobile plan. They all need your phone to be switched on and connected.

With Google Messages in the browser (Android)

If your Android phone uses the Google Messages app, you can write from any browser: Chrome, Edge, Firefox or Safari.

1. On your phone, open Messages, tap your profile picture or the account menu and choose the option to pair devices.
2. On your computer, go to messages.google.com/web and sign in with the same Google account.
3. Check that the emojis shown on your computer match the ones on your phone and confirm.
4. You’re ready to start writing. Your conversations appear on the screen and messages go out from your number.

Google is replacing QR code pairing with Google account pairing, so you may no longer see the code. Only one computer can be active at a time. If you don’t use it for a few weeks, it unpairs automatically.

With Phone Link on Windows

Windows 11 comes with the Phone Link app. It works with both Android and iPhone.

1. Open Phone Link on your PC and choose whether your phone is an Android or an iPhone.
2. With Android, install the Link to Windows app on your phone and scan the code shown on the screen. With iPhone, the connection is made over Bluetooth.
3. Accept the messages and notifications permissions on your phone.
4. Open the Messages tab and start typing.

With Android you’ll see your recent conversations and can send photos. With iPhone the options are more limited: there are no group chats or photo sending, and you only see the messages that arrive while the phone is connected.

With the Messages app on Mac (iPhone)

If you have an iPhone and a Mac, the Messages app on your Mac can send SMS to Android phones through your iPhone.

1. Sign in on your Mac and your iPhone with the same Apple Account.
2. On your iPhone, go to Settings > Apps > Messages > Text Message Forwarding.
3. Turn on the switch for your Mac.
4. Open Messages on your Mac and write to any number. Messages to phones that aren’t iPhones go out as SMS, in green bubbles.

If you already use Messages in iCloud on both devices, forwarding is included and you don’t need to turn it on separately.

Which option suits you, depending on your computer and phone

To chat with friends or reply to a specific customer, any of these options will do. The problem starts when you want to write to lots of people at once.

Why you shouldn’t send mass SMS from your phone

With the options above, you could copy and paste the same message a hundred times. Technically it works, but it has several problems:

• The sender is your personal number. The customer sees an unknown mobile number instead of your company name and becomes suspicious.
• Your carrier may block you. Personal plans aren’t designed for high-volume commercial sending, and many contracts prohibit it.
• You don’t know what happened. There are no delivery statistics and no easy way to know who received it.
• Unsubscribes are handled by hand. If someone asks not to receive any more messages, it’s up to you to remember.
• You waste a lot of time. Personalizing and sending messages one by one doesn’t scale.

That’s what mass SMS platforms are for: you send from your computer’s browser, but with your brand name, to your whole list at once and with reports.

How to send mass SMS from your computer, step by step

With an SMS sending platform, the process takes just a few minutes. Here’s how to do it in Mailrelay:

1. Create your account and buy a package of credits. You choose how many SMS you need and which country you’re sending to.
2. Add the numbers. Paste your list of mobile numbers or use the numbers you already have in your email contact lists.
3. Choose the sender. Type your company name, 3 to 11 characters long and with no spaces. That’s what the customer will see instead of a number. To send to Spain, register it first under SMS > SMS alias registry.
4. Write the message. Up to 160 characters, or 70 if you use emojis or special characters. The editor warns you in real time if the text is too long and gets split into several SMS.
5. Run a test. Send it to your own phone and check the text and the link.
6. Send or schedule the campaign. Afterwards, check the statistics to see how many messages were delivered.

How much it costs to send SMS from your computer

The options that use your phone are free, but each SMS comes out of your mobile plan. Most current plans include unlimited texts to domestic numbers.

On a platform, you pay per message sent. Here are some of Mailrelay’s packages for Spain, excluding VAT:

Credits expire after one year and there is no commitment. A message longer than 160 characters is charged as several SMS. You’ll find the rest of the countries on our SMS pricing page.

Legal requirements for sending SMS to your customers

A promotional SMS is an electronic commercial communication, just like an email. In Spain, the LSSI and the GDPR apply:

• Consent. You need the recipient’s prior permission. The exception is your existing customers, if you write to them about products similar to the ones they already bought from you and you gave them the option to opt out when you collected their data (article 21 of the LSSI).
• Identification. The message must make it clear who is sending it.
• Easy opt-out. Include a way to unsubscribe and always respect it.
• Sender registration. Since 15 September 2026, SMS sent to Spanish mobile numbers with an alphanumeric sender (your brand name) must use an alias registered in the CNMC Alias Registry. If it isn’t registered, the carrier blocks the message. In Mailrelay you register it yourself from the dashboard, under SMS > SMS alias registry, before your first campaign.

Transactional SMS, such as a verification code or a notice that your order has shipped, aren’t advertising. Even so, don’t slip offers into them.

What to use SMS for in your business

SMS messages are almost always read, and within minutes, so they work best for short, time-sensitive messages. Some common uses:

• Appointment reminders for clinics, hair salons or garages.
• Order and shipping notifications for online stores.
• Verification codes, such as OTPs.
• Time-limited offers, such as a 24-hour flash sale.
• Payment reminders before an invoice is due.

Three sample messages you can adapt:

TALLERGARCIA: Hi Ana. Just a reminder about your appointment tomorrow at 10:00 am. If you can’t make it, reply CHANGE. Thank you.

MODALUNA: Today only, 20% off the whole store with code LUNA20: https://example.com/sale Opt out: reply STOP

CLINICASOL: Your appointment on Thursday the 12th at 5:30 pm is confirmed. Address and directions: https://example.com/appointment

For more ideas, see what SMS marketing is and how to combine it with other channels.

SMS, email or WhatsApp: when to use each one

They don’t compete with each other. Each channel has its moment:

A combination that works well: send the full offer by email and then, on the last day, a short SMS to remind people it’s ending.

How Mailrelay helps you send SMS from your computer

With Mailrelay’s SMS service, you send your messages from the same web dashboard as your newsletters, with nothing to install. You can use the mobile numbers you already have in your contact lists or paste in a new list.

You choose a sender with your company name, the editor warns you if the text is split into several SMS, and the statistics show you how many messages were delivered. Packages start at 350 SMS to Spain for €12.50 excluding VAT, with no commitment.

And for email, the free account includes up to 80,000 emails a month and 20,000 contacts, with human support on every plan.

Frequently asked questions about sending SMS from your computer

Can you send SMS from your computer for free?

Yes. With Google Messages on the web, Windows Phone Link or the Messages app on Mac, you send SMS from your number without paying anything beyond your mobile plan. Your phone has to be switched on and connected.

Can I send SMS from my PC without my phone?

Not with the free options: the message always goes out from your phone. If you don’t want to depend on your phone, you need an SMS platform, which sends the messages from the web with your company name.

How do I send an SMS to many contacts from my computer?

Use a mass SMS platform. You upload the list of numbers, choose the sender, write the message and send it to everyone at once. That way your carrier won’t block you, and you get delivery statistics.

Can I use my company name as the sender?

Yes, with an SMS platform. The sender can be 3 to 11 characters long. If you send to Spanish mobile numbers, that name must be registered in the CNMC Alias Registry. In Mailrelay you can register it from the dashboard, under SMS > SMS alias registry.

How many characters can an SMS have?

160 with the standard alphabet, and 70 if you use emojis or special characters such as some accented letters. If the text is longer, it is split into several SMS and each one is charged.

Related articles

• What mass SMS is and how to send it
• SMS sending platform: what it is and how to choose one
• SMS marketing
• MMS
• Payment reminder: email, SMS and WhatsApp examples