Post Size Calculator
The formula
What the post size tells you
The bottom line for post size and the margin it represents — the two numbers every owner checks before anything else.
Calculation: profit = revenue − costs; margin = profit ÷ revenue. Enter your inputs and every substitution is shown below the result.
Reading the result
A positive result with a sub-5 % margin is fragile; read the margin band, not just the sign.
Limitations and best practice
Accrual vs cash: this is P&L arithmetic — a profitable business still fails without the cash to pay Friday.
This calculator gives an estimate based on standard formulas; it is not professional financial, medical, legal or engineering advice. Verify anything you plan to act on with a qualified professional and your own records.
Frequently asked questions
Is margin the whole story?
Which costs count?
Source & methodology
Standard income-statement arithmetic.
Post Size: the number, the method and the caveats
You are here because you need a specific number, and you want to see how it was produced before you rely on it. Post Size is the kind of number people argue about from memory. This page ends that argument with arithmetic you can watch happen: enter your figures, get Post Size in real time, and see every substitution printed below.
Construction arithmetic punishes rounding: material orders sized on a casual Post Size end in short loads or expensive leftovers. profit = revenue − costs; margin = profit ÷ revenue is the exact path the tool follows, and the waste allowance you enter is where professional estimating separates from DIY.
Like most useful measures, Post Size is a summary, and summaries hide as much as they reveal. The companion outputs and the input table are here to reopen what the headline compressed.
What makes a calculation page trustworthy is that its copy is derived from its own arithmetic: here post size = $123,750.00, recomputed every time a field changes, and the sensitivity section ranks the inputs that move the result — Revenue / gross value first, at ≈13.9 % of the headline for a ten-percent error either way in that input. Work down the page and by the end you could re-derive the result in a spreadsheet from memory.
Every input in Post Size, and what it does to the answer
One formula, published in full: profit = revenue − costs; margin = profit ÷ revenue. Anything you can read, you can reproduce in a spreadsheet, and that reproducibility is the whole point of printing it rather than hiding it behind a button.
Revenue / gross value ($) (example value 172,500) is a numeric input whose unit is fixed by the label; a wrong unit is a wrong answer wearing a plausible disguise. The example value is there to demonstrate the mechanics, not to describe your situation — overwrite it.
Total costs ($) (example value 48,750) is a numeric input whose unit is fixed by the label; a wrong unit is a wrong answer wearing a plausible disguise. Replace the example with the figure from your own records — the tool recomputes instantly and the printed steps follow your numbers.
Periods to compare per-month figures (example value 23) is a plain measured quantity — the unit shown in the label is the unit the formula expects. Be precise about the boundary (exact date, start of month); time inputs decide the exponent in most formulas.
A fully worked Post Size example
Abstract formulas are hard to trust, so here is the complete substitution using the default inputs, written the way an examiner would want it. Starting figures: Revenue / gross value ($), Total costs ($), Periods to compare per-month figures. The computed post size comes out at $123,750.00, which the interpretation band labels “Exceptional — check for omitted costs”.
- Profit = $172,500.00 − $48,750.00 = $123,750.00
- Margin = ÷ revenue = 71.7 %
Margin — 71.7%. Compare it against the main result of $123,750.00 before drawing conclusions.
Cost coverage ratio — 3.54 ×. Read next to the headline, this is the figure that shows the shape of the trade-off.
Per period — $5,380.43. If your inputs change, this is usually the first companion figure to move.
Keep this worked example open while you enter your own figures: matching the shape of the substitution is the fastest way to spot a unit or convention mistake.
How far Post Size can reasonably move
Single-point answers invite false confidence, so the same engine was run across a band around the input that matters most here. Each row is a full recalculation of Post Size, not an interpolation.
| Revenue / gross value setting | Post Size |
|---|---|
| 80 % of the example value | $89,250.00 |
| 90 % of the example value | $106,500.00 |
| example inputs | $123,750.00 |
| 110 % of the example value | $141,000.00 |
| 120 % of the example value | $158,250.00 |
The corridor runs from $89,250.00 to $158,250.00 across that band — which is the range worth planning inside rather than the single $123,750.00 point estimate. Reproduce it in the form above by editing Revenue / gross value alone; the substitution steps will follow your figures exactly.
Where Post Size is fragile — and where it is not
Generic advice says “it depends on your inputs”; this section says exactly how much. Each field was perturbed by ±10 % in isolation and the post size recomputed, so the ranking below is measured rather than asserted. For Post Size the ranking is measured rather than guessed, and it belongs to these defaults: shift the starting point and the order can shift with it.
- Revenue / gross value: ten percent up gives $141,000.00, ten percent down gives $106,500.00 — ≈13.9 % of the post size either way
- Total costs +10 % → Post Size = $118,875.00 · −10 % → $128,625.00 (the post size shifts ≈3.9 %)
Revenue / gross value is the dominant lever here: ten percent either way moves the result by about 13.9 %, from $106,500.00 to $141,000.00. Measure that input from a document rather than from memory, and treat Total costs as the second priority (≈3.9 % per ten percent). The rest of the inputs earn only a rounding-error of attention, and that asymmetry is the practical payoff of measuring rather than asserting.
Reading the result: bands, zones and thresholds
A number on its own is trivia; a number against a range is intelligence. The default case lands in the “Exceptional — check for omitted costs” band, and bands are deliberately wide because real situations overlap. Before treating the band as fact, note its width: ten percent either way on Revenue / gross value already spans $106,500.00 to $141,000.00. The practical reading rules: compare against your own history before comparing against other people; treat band boundaries as zones, not walls — one point on the wrong side of a threshold rarely changes a real outcome; and when a companion output contradicts the headline, believe the pair.
In Construction & Home Improvement, Post Size is one instrument in an orchestra: on its own it is a number, next to Margin and Cost coverage ratio it becomes a diagnosis. The tools linked above exist so the headline never has to carry that weight alone.
Why Post Size results go wrong — and how to prevent it
Accrual vs cash: this is P&L arithmetic — a profitable business still fails without the cash to pay Friday. This calculator gives an estimate based on standard formulas; it is not professional financial, medical, legal or engineering advice. Verify anything you plan to act on with a qualified professional and your own records.
Chasing precision in Total costs ($) while Revenue / gross value ($) is still a guess. The sensitivity ranking above shows exactly where the accuracy budget should go.
Attention is also misallocated between fields. Having measured this engine, we can say where it belongs: Revenue / gross value first, everything else second.
Another is comparing across contexts: a Post Size computed with one set of conventions should never be lined up against a figure computed with another. Check the inputs behind both before ranking them.
Six things to confirm before acting on Post Size
- Note the date and the inputs beside the number so the figure can be audited later.
- Record the date and the inputs alongside the number so future-you knows what was assumed.
- Put Revenue / gross value under a magnifier; the sensitivity table above is the reason why.
- Recompute once with the dominant input deliberately set low, and see whether the decision changes.
- Confirm the example values are plausible for your own situation before replacing them.
- Repeat the ±10 % test on the inputs that matter and see whether the decision — not just the number — still holds.
Step by step: getting a trustworthy Post Size out of this tool
The tool does the arithmetic; the routine below is what makes the arithmetic trustworthy. Five steps, a minute total — and afterwards you will know not just what the number is, but which assumption produced it.
Step 1 — one document, one pass. Open the statement, label or record that holds revenue / gross value ($), total costs ($), periods to compare per-month figures and transcribe straight into the form. Transcription from a single source removes the mismatch errors that appear when figures are assembled from three different places. If the verdict changes with a ten-percent nudge, report the nudge alongside the number.
Step 2 — start from the case you can defend. Enter pessimistic-but-honest figures first; the optimistic run is a ceiling, not a plan. A conclusion that holds on conservative inputs holds everywhere. Precision is a promise you make about your data; make sure your inputs can keep it.
Step 3 — measure what deserves measuring. The ranked levers above tell you where a careful figure pays off. Everything else can stay approximate, which is a licence to stop hunting for data you do not need. When in doubt, prefer the boring input: the interesting one is usually the one you misread.
Step 4 — stress before you commit. A decision that survives a ten-percent squeeze on its two biggest inputs needs no luck to be sound. One that does not survive is a decision about hope, not about arithmetic. A figure nobody can reproduce is a figure nobody will act on twice.
Step 5 — record the context, not just the number. Note today’s date and the inputs alongside the $123,750.00 output. Six months from now the context is what turns this figure into a trend. The test of a good estimate is not that it feels right but that it changes what you do.
From calculation to decision: where Post Size earns its keep
In Structural the figure computed here is usually the first one somebody asks to see. Having it — with the formula behind it — changes your position in the conversation from participant to reference. A figure with a date beside it becomes evidence; without one it stays an anecdote.
Used properly this is a five-minute filter that saves weeks. Compute Post Size, reject what fails, and only then bring in the expensive analysis for the survivors. The input you reach for first is usually the one you measured longest ago.
Nothing here is stored or transmitted, so the habit of checking is free: open the page, re-enter current figures, compare with the number you saved last time. Repeating a calculation with the same numbers proves only that the arithmetic is reliable — which is worth knowing.
Post Size — frequently asked questions
What affects Post Size the most?
Measured on this engine, Revenue / gross value is the dominant lever: moving it ±10 % shifts the post size across $106,500.00 to $141,000.00 — about 13.9 % of the headline, with Total costs next at ≈3.9 %. The ranked list in the sensitivity section is computed live, not asserted from a template.
Which matters more: total costs or revenue / gross value?
For Post Size, Revenue / gross value wins the head-to-head (≈13.9 % against ≈3.9 % per ten-percent change). Knowing which input dominates is the difference between careful work and merely slow work.
What is a typical Post Size?
There is no honest universal average for Post Size, but there is a reference point: the defaults on this page produce $123,750.00 (Exceptional — check for omitted costs). Replace the inputs with your own and compare — that comparison is the useful meaning of “typical”.
How do I calculate Post Size by hand?
profit = revenue − costs; margin = profit ÷ revenue is the entire method. Work the inputs in that order — Profit = $172,500.00 − $48,750.00 = $123,750.00 — and you will reach $123,750.00 on the default figures, the same number this tool prints.
What happens to Post Size if revenue / gross value changes by 10 %?
The engine was re-run with that field moved by ten percent while everything else stayed fixed: the post size goes across $106,500.00 to $141,000.00, a swing of roughly 13.9 % around the $123,750.00 baseline. That ratio is the practical definition of how much this input matters.
Is the Post Size result of $123,750.00 good or bad?
The tool answers “what”, not “whether”: $123,750.00 carries the verdict “Exceptional — check for omitted costs” for the default case, which is a starting interpretation rather than a verdict on your situation. Re-run with your own figures and compare the bands.
Do I add waste to Post Size?
Yes — standard waste allowances run 5–15 % depending on material and cut complexity, and this tool expects them inside your inputs. Leaving waste out is the most frequent way a Post Size under-orders.
How often should I check Post Size?
Whenever an input changes by more than a few percent, and otherwise on the rhythm of your decisions — before a purchase, a review, a renewal. Post Size is a snapshot, not a subscription; stale snapshots are the most common silent error in Construction & Home Improvement planning.
Is margin the whole story?
No — capital turnover decides ROE. A 5 % margin at 10× turnover beats a 30 % margin at 0.5×.
Which costs count?
Everything below the definition you chose. State gross or net, and keep the same definition across periods.
Is my data private on this page?
Yes — computation happens locally in your browser, with no account, no tracking of your inputs and nothing sent to a server. The printed formula is the whole story of what happens to your figures.
Key terms on this page
- Margin
- 71.7% for the Post Size worked case; it sits next to the main result because it carries context the headline leaves out.
- Cost coverage ratio
- 3.54 × on the example inputs — a companion figure printed beside the headline of Post Size so that no result is read in isolation.
- Per period
- $5,380.43 for the Post Size worked case; it sits next to the main result because it carries context the headline leaves out.
- Post Size
- The primary output of this tool: $123,750.00 for the default inputs, computed exactly from profit = revenue − costs; margin = profit ÷ revenue.
- Worked example
- The calculation written out in full so that nothing on this page has to be taken on trust.
- Verdict band
- The interpretation attached to a result (“Exceptional — check for omitted costs” on these inputs), which turns a bare number into a position on a scale.
- Sensitivity (±10 %)
- How far the Post Size moves when a single input is nudged ten percent either way; the ranked list on this page is computed live from this engine.
The provenance of this Post Size calculation
Everything above runs on one stated formula, applied without hidden coefficients: profit = revenue − costs; margin = profit ÷ revenue. Source of record: Standard income-statement arithmetic. Where a professional version of this calculation differs, it differs in inputs and jurisdiction-specific coefficients, not in the algebra — which is why re-checking your inputs beats hunting for a second calculator.
Nothing here replaces a qualified professional, and nothing here is approximate either — the arithmetic is exact, and the honesty is in the inputs you supply. The design constraint was set by usefulness rather than by comfort: an estimate you can interrogate beats an answer you have to trust.
Turning this Post Size into a decision
Re-run the calculation with your own figures, stress the two most sensitive inputs by ±10 %, and only then act on the result.
Whoever you are (people who need one trustworthy number before their next decision), the next step is the same: replace the example inputs with your own, note the date, and re-run whenever a figure moves. In Construction & Home Improvement, a dated figure is a trend, and an undated one is a rumour.