PRL Length Management (prl-length-management)

When to trigger

• The manuscript is over the length limit (or you suspect it is)
• You need to know how much "room" a figure or equation actually costs
• You must decide what to cut, compress, or push to Supplemental Material
• A reviewer/editor flagged the Letter as too long
• Late stage: content, figures, and SM are stable and now must fit

How the PRL length limit works (the deductible model)

A Letter is short — on the order of ~3750 words / roughly four journal pages including figures and references; verify the current limit on the APS author page. The key feature is that the limit is a deductible budget: it is not just running text. Against the same total budget you must count, in current APS practice:

• The body text (the largest term).
• Figures — each figure consumes word-equivalents that scale with its printed area / aspect ratio; a large or double-column figure costs more.
• Equations — displayed equations consume word-equivalents (roughly per line/equation).
• References — the reference list counts against the budget.
• The abstract and table material also count.

APS provides a formula / length guide and an automated length check on submission. The practical consequence: a beautiful extra figure can cost you a paragraph of text. Budget figures and text together, not separately.

Triage order (cut from cheapest loss to most painful)

1. Move to SM first. Derivations, extended data, secondary controls, full error budgets → Supplemental Material (see prl-supplementary). This is almost always the largest, lowest-pain saving.
2. Compress figures. Drop non-essential panels; convert a double-column figure to single-column; merge two figures showing related points. Each reclaims word-equivalents.
3. Prune equations. Keep only claim-defining equations inline; move derivation steps to SM; inline short results within a sentence rather than displaying them.
4. Trim references to those that establish importance or are needed for trust; consolidate where APS style permits.
5. Tighten prose (apply prl-writing-style): remove padding, hedging, and figure-transcribing sentences.
6. Cut scope as a last resort: demote a supporting claim entirely.

Cost-awareness table

Checklist

• You have run the current APS length formula / length-check, not just a word count
• Figures and equations are counted against the budget, not ignored
• Derivations and extended data are in SM, not the body
• No double-column figure remains unless the data demand it
• Only claim-defining equations are displayed inline
• Reference list is pruned to importance + trust essentials
• Prose padding/hedging removed (cross-check prl-writing-style)
• The Letter still stands alone after trimming (cross-check prl-supplementary)

Anti-patterns

• Counting only words and being surprised the figures blow the limit
• Trimming load-bearing content (the key control, the headline uncertainty) to fit
• Shrinking fonts in figures to save area (fails legibility instead)
• Padding the SM until the Letter no longer stands alone
• Leaving a decorative double-column figure that costs a paragraph
• Discovering the over-length only at submission, after content is frozen

Output format

【Current length vs. limit】over by ~X (per APS formula, verify)
【Figure/equation/reference budget counted】yes / redo with formula
【Moved to SM】list
【Figures compressed】list (double→single, panels dropped, merged)
【Equations pruned】list
【References pruned】from N to M
【Still stands alone】yes / fix
【Next】prl-cover-letter or prl-submission

The word/page limit, the length formula, and per-element costs are exactly the kind of volatile specifics that change — always verify the current limit and length guide on the official APS / PRL author page.