How many days will your Gmail campaign take?

It's a rolling 24-hour window, not a daily reset

Gmail's limit doesn't reset at midnight. It works on a rolling 24-hour window: each email you send "occupies" a slot for the next 24 hours, and the slot frees up exactly 24 hours after it was used.

In practice: if you send your full 500 at 10am on Wednesday, you can't send again until around 10am on Thursday. If you spread those 500 across Wednesday afternoon, capacity comes back gradually across Thursday afternoon. This is why "I'll just wait until tomorrow morning" sometimes doesn't work — tomorrow morning may still be inside yesterday's window.

For campaign planning, the safe mental model is simple: treat each batch as locking you out for a full 24 hours from the moment you hit send. That's exactly how the day-by-day breakdown above is calculated.

What counts toward the limit (more than you'd think)

• Every recipient counts individually. Each address in To, CC, and BCC uses one slot. CC'ing your colleague on 100 campaign emails costs you 100 extra slots.
• Replies and forwards count. The limit isn't just for outbound campaigns — every reply you send to a client and every email you forward during the day draws from the same allowance.
• Auto-responders count. If your vacation responder replies to 40 people while a campaign is running, that's 40 slots gone.
• Sends from any connected tool count. Anything that sends through your Gmail account — a CRM, a mail merge script, a scheduling tool — shares the same single allowance. Gmail doesn't distinguish between "you" and "software acting as you."

The Workspace quota catch: paying doesn't mean 2,000/day immediately

A detail that surprises many new Workspace customers: the 2,000/day limit isn't granted the moment you subscribe. Google Workspace free trial accounts are limited to 500 emails per day — the same as a free Gmail account. After you convert to a paid subscription, Google raises the limit only once your domain has cumulatively paid at least $100 USD, and the increase can take up to 75 days after you reach that threshold.

So if you signed up for Workspace last month specifically to send bigger campaigns, check your actual current limit before planning around 2,000/day — you may still be operating at 500. When in doubt, run the calculator above on the "Free Gmail" setting for a conservative estimate.

The unofficial hourly pace

Google's documentation only publishes daily limits. In practice, many senders and email tools have observed that Gmail also throttles bursts — sending too many emails in a short window can cause temporary failures or delays even when you're well under the daily cap. This hourly behavior isn't in Google's official documentation, so treat it as a practical observation rather than a published rule.

The safe approach: don't fire hundreds of emails in one minute. Spacing sends across the day is gentler on your account and, as a bonus, tends to look more natural to spam filters on the receiving end too.

What happens if you go over

Exceeding the limit triggers a temporary send block — Gmail shows a message like "You have reached a limit for sending mail," and you typically regain the ability to send within 1 to 24 hours. On a first offense, it's an inconvenience, not a catastrophe: your account isn't banned and your queued emails aren't lost forever, though bounced campaign emails may need to be re-sent.

Repeated violations are a different story. Accounts that keep hitting the ceiling can face longer blocks or, in persistent cases, permanent restrictions. If your sending needs consistently exceed your account's limit, the honest answer is that Gmail isn't the right sending infrastructure for that volume — no tool changes the underlying account limit.

How to plan a campaign that stays under the limit

• Start with the calculator above. Contact count ÷ daily limit, rounded up, is your minimum campaign duration. Add a day of slack for real life.
• Leave a buffer for everyday email. Your replies, forwards, and CCs come out of the same allowance, so plan campaign batches below the hard cap.
• Clean your list first. A high bounce rate is a spam signal independent of volume. Remove obviously dead addresses before sending, not after.
• Ramp up gradually on newer accounts. A mailbox that normally sends 20 emails a day and suddenly sends 500 looks suspicious. Growing volume over a couple of weeks is safer than jumping straight to the ceiling.
• Send in smaller daily batches for anything time-flexible. If your campaign isn't tied to a date, sending 200–300 per day instead of the maximum keeps you far from every threshold and improves the odds of landing in the inbox.