Cartesia Pro $5 plan vs Sume TTS at 100K, 1M and 10M characters

Cartesia's Pro plan costs $5 a month and includes 100,000 credits, where one credit is one character, with overage at $65 per million credits. At 100,000 characters in a month Cartesia Pro is $5.00 against $4.75 on Sume; at one million it is $63.50 against $47.50; at ten million it is $648.50 against $475.00. Sume totals are before its 5.5% platform fee.

What Cartesia publishes

Cartesia's pricing page (read 2026-10-07) lists Pro at $5 a month with 100K credits, Startup at $49 and Scale at $299, with overage of $65, $45 and $38 per million credits respectively. It says 1 credit equals 1 character of text-to-speech. This post prices only the Pro plan, because the page's included credits for the other plans are outside this comparison.

Three monthly volumes

Cartesia total = $5 + overage characters x $65 per million. Sume total = characters x $0.0475 per 1,000, rounded up to the micro-dollar. The last column adds Sume's 5.5% fee.

What the table does and does not say

At the volumes shown, Sume is cheaper per character than Cartesia Pro overage, and with the fee it is still below Pro from 1 million characters up. At 100,000 characters the $5 plan and Sume with the fee ($5.01) are close. Cartesia's Startup and Scale overage rates are lower ($45 and $38 per million), and they come with higher plan prices, so a heavy user should price those tiers too. Sume's own list rate equals the Scale overage figure per the overage post.

Practical notes

• A Sume TTS request takes up to 20,000 characters, so longer scripts are sent as several jobs; each full job is $0.95 before fee.
• The Sume column counts usage only, drawn from the prepaid balance; Sume's subscription plans are priced separately on its pricing page.
• Voice quality and language coverage are not priced here; compare samples.