Cartesia credits to dollars vs Sume TTS: per minute and per hour

Cartesia's pricing page says one credit is one character and one minute of speech takes 750 to 800 credits (read 2026-10-07). Its plans work out to $0.05, $0.0392 and $0.0374 per 1,000 characters on Pro, Startup and Scale. Sume's TTS is $0.0475 per 1,000, so a minute (800 characters) is $0.038 and 1,000 minutes is $38.00.

Credits to dollars

Divide the plan fee by its credits and multiply by 1,000. Pro: $5 / 100,000 x 1,000 = $0.05. Startup: $49 / 1,250,000 x 1,000 = $0.0392. Scale: $299 / 8,000,000 x 1,000 = $0.037375. At 800 characters per minute that is $0.040, $0.0314 and $0.0299 a minute.

Why the Sume number looks like that

Sume's docs say TTS is character-metered at the Cartesia list times 1.25. $0.0475 / 1.25 = $0.038 per 1,000, a rate just above Cartesia's Scale-plan effective price and below its Startup and Pro ones. Sume's billed $0.0475 is itself below Cartesia's Pro-plan $0.05. The 25 percent premium is thus smaller than the spread between Cartesia's own plans.

That list is a per-use rate. Cartesia's plan rates assume you use the credits you pay for.

Transcription for comparison

Cartesia's page says an hour of transcription is $0.39 on the Scale plan (read 2026-10-07). Sume STT 1.0 is $0.01 per audio minute, or $0.60 an hour, with a maximum duration hint of 600 seconds. Sume's rate is 54 percent higher ((0.60 - 0.39) / 0.39). These may be different speech models, so this is a price comparison only.

How to choose

If speech is your whole workload, a Cartesia plan at the right size wins on price. If speech is one step of a video pipeline and you want to submit it through the same API as the video and read one usage ledger, the 25 percent is the cost of that. I did not test or compare voice quality.

Break-even against the Pro plan

Cartesia Pro is $5 for 100,000 credits. Sume matches $5 at 105,263 characters ($5 / $0.0475 x 1,000), so below about 105,000 characters a month Sume is cheaper than the $5 Pro fee, and above it Pro is cheaper per character if you fill it. For the Free plan, 20,000 credits cost nothing, which is 25 minutes of speech at 800 characters per minute.

At 1,250,000 characters a month, Startup is $49 and Sume is $59.38 (1,250 x $0.0475). At 8,000,000, Scale is $299 and Sume is $380. The gap on Scale is $81, or 27 percent, which is the price of staying on one API with video.