Generate 90-Character Google Ads Descriptions with AI

Tested prompts for google ads description generator 90 characters compared across 5 leading AI models.

BEST BY JUDGE SCORE GPT-5.4 6/10

The prompt we tested

You are an expert Google Ads copywriter specializing in high-converting description lines that comply with Google's 90-character limit.

Rules:
Write each description as a single line, maximum 90 characters (count spaces and punctuation). Include a clear value proposition and a strong call-to-action (e.g., Shop Now, Get a Quote, Learn More), use sentence case, avoid ALL CAPS words, excessive punctuation, and unsupported superlatives to stay Google Ads policy-compliant.

Product, service, or campaign details:
We sell eco-friendly bamboo toothbrushes with biodegradable packaging, free shipping on orders over $25, and a 30-day money-back guarantee. Target audience is environmentally conscious shoppers aged 25-45. Campaign goal is driving first-time purchases from our website.

Generate 5 distinct Google Ads description variations. For each variation, output it on its own line in this exact format:
1. [description] (XX chars)

Where XX is the exact character count including spaces and punctuation. Every description must be 90 characters or fewer. After the list, add one short line recommending which variation is strongest and why.

Model comparison

ModelQualityCostLatencyTokens
Claude Opus 4.7 4 $0.0358 9.5s 389 / 400
Claude Haiku 4.5 3 $0.0025 4.1s 271 / 454
GPT-5.4 6 $0.0026 5.3s 230 / 132
Grok 4.1 Fast Reasoning 6 $0.0001 22.1s 380 / 143

Outputs

Claude Opus 4.7 4/10
1. Eco-friendly bamboo toothbrushes with biodegradable packaging. Free shipping over $25. Shop now. (96 chars)

Let me recount and fix that one.

1. Bamboo toothbrushes, biodegradable packaging. Free shipping over $25. Shop sustainably now. (91 chars)

Let me provide accurate counts:

1. Switch to bamboo toothbrushes. Biodegradable packaging, free shipping over $25. Shop now. (90 chars)
2. Eco-friendly brushing made simple. 30-day money-back guarantee. Order yours today. (82 chars)
3. Ditch plastic for good. Bamboo toothbrushes with free shipping over $25. Shop now. (82 chars)
4. Brush greener with bamboo. Biodegradable packaging and free shipping over $25. Learn more. (90 chars)
5. Sustainable smiles start here. Try our bamboo toothbrushes risk-free for 30 days. Buy now. (89 chars)

Recommended: Variation 1 is strongest—it leads with a clear action, highlights the eco benefit, shipping offer, and CTA within the limit.
Judge notes: The output is visibly broken — it shows failed attempts, mid-stream corrections, and self-corrections before the final list, which is unprofessional and not production-ready; additionally, the character counts are inaccurate (e.g., variation 1 is actually 91 chars, not 90), undermining the core technical requirement of the task.
Claude Haiku 4.5 3/10
1. Switch to sustainable bamboo toothbrushes with free shipping on orders over $25. Shop now. (89 chars)

2. Eco-friendly bamboo toothbrushes, biodegradable packaging, 30-day guarantee. Order today. (89 chars)

3. Reduce plastic waste with our bamboo toothbrushes. Free shipping + 30-day money-back guarantee. (95 chars)

4. Sustainable bamboo toothbrushes delivered free over $25. Risk-free with our 30-day guarantee. (94 chars)

5. Make the switch to eco-friendly bamboo toothbrushes. Free shipping on orders over $25. Shop now. (98 chars)

Let me revise variations 3, 4, and 5 to comply with the 90-character limit:

1. Switch to sustainable bamboo toothbrushes with free shipping on orders over $25. Shop now. (89 chars)

2. Eco-friendly bamboo toothbrushes, biodegradable packaging, 30-day guarantee. Order today. (89 chars)

3. Reduce plastic waste with bamboo toothbrushes. Free shipping over $25. Learn more today. (88 chars)

4. Sustainable bamboo toothbrushes with free shipping over $25. Try risk-free for 30 days. (88 chars)

5. Eco-friendly bamboo toothbrushes in biodegradable packaging. Free shipping over $25. Shop now. (94 chars)

Revision for #5:

5. Biodegradable bamboo toothbrushes with free shipping over $25. Get yours risk-free today. (90 chars)

**Strongest variation:** #1 – It clearly states the sustainability angle, highlights the free shipping incentive, and uses a direct CTA ("Shop now") that drives conversions. The benefit-focused copy resonates with eco-conscious buyers.
Judge notes: The output is messy and untrustworthy — it presents non-compliant descriptions (95, 94, 98 chars), attempts self-corrections mid-output, still produces a non-compliant final #5 (94 chars), and the character counts for the "corrected" versions are likely inaccurate, fundamentally failing the core task requirement of delivering 5 clean, verified, compliant descriptions.
GPT-5.4 6/10
1. Switch to bamboo toothbrushes with biodegradable packs. Shop now with free shipping. (84 chars)
2. Eco-friendly bamboo toothbrushes with a 30-day guarantee. Shop now and save. (80 chars)
3. Choose bamboo toothbrushes in biodegradable packaging. Order now with confidence. (83 chars)
4. Make your routine greener with bamboo toothbrushes. Shop now and try risk-free. (85 chars)
5. Sustainable bamboo toothbrushes with free shipping over $25. Buy now and save. (82 chars)

Strongest: 4, because it pairs an emotional eco benefit with a low-risk, action-driven CTA.
Judge notes: The descriptions are functional and policy-compliant, but they're generic and undersell the product's differentiators — several CTAs are weak filler ("Shop now and save" repeated), the character counts are unverified and likely inaccurate (e.g., #1 counts as 87 not 84), and no variation meaningfully combines all three key selling points (bamboo + biodegradable packaging + 30-day guarantee + free shipping threshold) into a compelling, tight line.
Grok 4.1 Fast Reasoning 6/10
1. Eco-friendly bamboo toothbrushes. Biodegradable packaging. Free ship over $25. Shop now! (88 chars)

2. Sustainable bamboo toothbrushes with 30-day guarantee. Free shipping $25+. Shop now! (85 chars)

3. Bamboo toothbrushes in biodegradable packaging. Free ship over $25. Order now! (80 chars)

4. Eco bamboo toothbrushes, free shipping on $25+. 30-day money-back. Buy today! (76 chars)

5. Go green: bamboo toothbrushes, biodegradable packs. Free ship $25+. Shop now! (78 chars)

Variation 1 is strongest for balancing key benefits with a compelling, direct CTA.
Judge notes: The character counts are unverified and likely inaccurate (e.g., variation 1 counts as more than 88 chars), and "Free ship" is an awkward truncation that would need editing before production use.

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