Compare things before buying
Everyday
Give your budget, use and non-negotiables, and get three candidates compared on reasons and downsides.
Fill the blanks and it copies as you filled it
Help me decide what to buy. - What: - Budget and what I'll use it for: - What I can't give up: - Three candidates. One line on why, one line on the downside, for each
0 of 3 blanks filled · anything left blank copies with its brackets
What this prompt does
Compared with asking the same thing without the length and format lines.estimate
Estimated output tokens
700
Asked loosely
320
This prompt
Energy (Wh)
1.215
Asked loosely
0.423
This prompt
Tokens estimated from characters; energy measured by Jegham et al. 2025.
What that saves
15.8 Wh · 5.54 gCO₂e · 74 mL — assuming 20 uses a day — the global average is 3.7 (Chatterji et al. 2025)
Tap a card for how the conversion was done.
Reported backfire — Specifying output lengthSpecifying a length longer than needed backfires (a 34% increase in 11% of scenarios)
Reported backfire — Asking for several options at onceAn increase of over 50% in 9% of scenarios. Don't use it on questions with one right answer
Where these figures come from
Published figures for the rule itself — not what this prompt saves.
Specifying output length
38.7%mean reduction · 95% CI 29.7–47.7%
Podder et al. 2026 BP#5 · 18 use cases / 57 prompts
by modelGPT-4o 35%Command R+ 49%Mistral-7B 32%
Reduced in every scenario. No backfire reported
Asking for several options at once
36%mean reduction · 95% CI 25–47%
Podder et al. 2026 BP#1 · 22 use cases / 71 prompts
by modelGPT-4o 50%Command R+ 44%Mistral-7B 39%