On an Opus account (NovelAI's top subscription tier), NovelAI Diffusion V5 still costs 0 Anlas (NovelAI's generation credits) up to Normal size (832×1216) at 28 steps and one image per request; Large (1024×1536) is where 45 Anlas starts coming out of your balance. From September 21, 2026, your unused subscription Anlas resets to 0 when your subscription period ends, and the balance endpoint has moved from api.novelai.net to image.novelai.net. The reset is tied to the end of your period, not to the effective date: on September 22, the day after it took effect, this account's balance was still untouched.
Overview
V5 shipped on 2026-08-21, and with it came a "battery" usage limit on Opus subscriptions. The announcement doesn't say how much a single generation draws or where you can see it, so I ran the numbers myself against the API. The reset itself is still a policy statement here: this account's paid period runs to September 29, so the day-after query only shows that nothing is wiped on the effective date. I measured on 2026-09-11 and 2026-09-13, and queried once more on 2026-09-22.
I wrote this for two groups: people deciding whether to keep or cancel Opus, and people driving the NovelAI API directly from tools like ComfyUI nodes. In that order: the per-size cost table, the new usage field, and the endpoint that moved.
The problem
Querying your balance at the old address now returns a 400. The response body is a single line:
GET https://api.novelai.net/user/subscription → 400
{"statusCode":400,"message":"Please refresh NovelAI.net. If using a third-party tool, update to the image URL."}
On top of that there's a policy change. The official blog post (2026-08-20) says a rechargeable battery-style usage limit applies to V5 only, refilling automatically over roughly a week, and that starting 31 days after the V5 release, unused subscription Anlas is reset to 0 when a subscription period ends. V5 launched on August 21, which puts the effective date at September 21.
Image models older than V5 and the text models stay unlimited. But Anlas was visibly draining on an Opus account while generating with V5, so I needed to find out under exactly which conditions it gets charged.
What I measured
On an Opus account (tier: 3) I generated one image at a time with the same prompt, seed, and 28 steps, calling GET https://image.novelai.net/user/subscription before and after each generation and diffing trainingStepsLeft. Balance queries have to go to that host now to get a normal response.
| Model | Size | Anlas charged |
|---|---|---|
nai-diffusion-5-full |
512×768 (Small) | 0 |
nai-diffusion-5-full |
832×1216 (Normal) | 0 |
nai-diffusion-5-full |
1024×1536 (Large) | 45 |
nai-diffusion-4-5-full |
832×1216 (Normal) | 0 |
nai-diffusion-5-curated |
512×768 (Small) | 0 |
Within what I measured, everything up to Normal size (832×1216) at 28 steps and one image per request was 0 Anlas, and subscription Anlas started coming out at Large (1024×1536). The ComfyUI node (ComfyUI_NAIDGenerator) implements the Opus free tier as up to 1,048,576 pixels (1024×1024), up to 28 steps, and one image — I didn't measure 29 steps, multi-image batches, or the exact pixel boundary this time. Large size is where subscription Anlas gets charged, and that subscription Anlas (fixedTrainingStepsLeft) is what disappears when your subscription period ends after September 21. If you only cancel renewal and still have paid time left, the clock is the end of that paid period.
I queried the same account again once the effective date had passed. On 2026-09-22 the subscription Anlas read 9,898, the same figure as the September 13 sample, and expiresAt was still 1790674321, which is 2026-09-29 18:32 KST. So at least on this account nothing was wiped on the effective date; it is simply still inside its paid period. That is one sample, but it rules out a blanket reset on the day itself. I'll query again after that renewal and report what the reset does.
The test account held 9,961 subscription Anlas and 32 purchased Anlas (purchasedTrainingSteps) as separate line items, and the 45 for the Large generation came out of subscription Anlas only (9,961 → 9,916). If the total the web UI shows doesn't match, check whether it's the sum of the two. The reset targets the subscription side; whether purchased Anlas is exempt is listed under Unverified below.
The battery sits at the end of the subscription response, in a usage field. It didn't move once across four V5 generations. When I queried again 46 hours later, percent had dropped to 98 — after a handful of additional V5 generations from the web UI on this account in between (count not recorded). So the battery is a meter that really does go down, and timeUntilNextPercent stayed at 7,888 even at 98%, so it isn't a live countdown. A third sample nine days later was back at 100%, so it does recharge, but September 19 — the date NovelAI's official account gave for the usage limit renewal, seen 2026-09-14 — falls inside that gap, so I can't tell natural recharge from the renewal. timeUntilNextPercent read 7,888 in all three samples. That's as far as the evidence goes:
"usage": {
"percent": 100,
"isNegative": false,
"timeUntilNextPercent": 7888
}
I checked the V5 model IDs while I was there. Both nai-diffusion-5-full and nai-diffusion-5-curated returned 200 with an image, and the PNG Source metadata read NovelAI Diffusion V5 0ADF9AB7 and NovelAI Diffusion V5 DB276663 respectively. Sending an ID that doesn't exist returns Validation error: model nai-diffusion-5-nonexistent doesn't exist.
For reference, a Japanese write-up (note.com, 2026-08-21) put V5 generation cost at 11 Anlas for Small, 26 for Normal, and 39 for Large, while my measurement for Large was 45. That write-up doesn't state step count or account tier (the web UI default is 23 steps; my runs were 28), so it isn't directly comparable. Logged out, the web UI showed 26 Anlas for the default settings (V5 Curated, 23 steps, Normal size), which is the non-subscriber rate with no free tier.
What to do
- Keeping Opus doesn't exempt you from the V5 battery usage limit. That said, within what I measured, the Anlas charging rules are the same as V4.5 — up to Normal size, 28 steps or fewer, one image at a time, it's 0 Anlas. Battery capacity and recharge rate are still unknown. A second sample 46 hours later showed 98%, but I didn't record how many images were generated in between, so how much use it takes to get blocked stays unverified.
- If you plan to cancel, order matters. After September 21, whatever subscription Anlas is left disappears when your subscription period ends, so it's better to burn the subscription side down before that period runs out — with Large generations or multi-image batches.
- In third-party tools, point the balance query at
image.novelai.net. If generation works but the balance won't load, that's almost always this.
Image: the sample output was generated with NovelAI Diffusion V5.
Takeaways
On Opus, V5 is still free up to Normal size at 28 steps, and if you plan to cancel, spend down your subscription Anlas before your paid period ends once the reset policy takes effect on September 21, 2026. If a tool can generate but can't read your balance, the old host is the most likely cause, so check which balance endpoint it calls.
Unverified
- How the subscription Anlas reset actually behaves: the effective date has passed, but this account still has paid time left, so there was nothing to observe. I'll re-query after its renewal on 2026-09-29.
- Battery capacity and recharge rate: three samples show it going down and coming back up, but the generations in between weren't counted and the September 19 renewal falls inside the gap, so I couldn't derive a drain or recharge rate.
- The reset notice text and battery display in the web UI: my browser session was logged out, so I couldn't capture the subscriber view.
- Whether purchased Anlas is exempt from the reset: inferred from the official post mentioning subscription Anlas only.
Changelog
| Version | Description |
|---|---|
| 1.0 | 2026-09-11 first written (measured on an Opus account via API) |
| 1.1 | 2026-09-13 second battery sample added (re-queried 46 hours later) |
| 1.2 | 2026-09-22 re-queried the day after the effective date (subscription Anlas unchanged at 9,898, battery back at 100%) |
| 1.3 | 2026-09-30 added the AI disclosure line (no content change) |
AI disclosure: translated and edited with AI assistance (Claude) from my Korean original. Measurements were run with Claude Code under my supervision; I reviewed the result.
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