WAN Optimization Calculator
The formula
What the wan acceleration gain tells you
Combined payoff of TCP proxying and data reduction on a slow, long pipe — both the window math and the dedupe multiplier.
Calculation: Proxy on ⇒ per-flow window 512 KB on LAN leg; transfer = GB×8192 Mb ÷ min(link, win/RTT) ÷ dedupe. Enter your inputs and every substitution is shown below the result.
Reading the result
Proxying fixes latency; dedupe fixes volume. Chatty CIFS traffic usually needs the proxy most — byte reduction cannot repair a stalled window.
Rules of thumb: Branch-office file sync over 120 ms RTT typically lands a 3–6× combined factor.
Limitations and best practice
Dedupe ratios are workload-dependent: already-compressed media sees ~1.0×, while repeated branch file shares hit 5–10×; size appliances on your own mix.
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
Does QUIC make appliances obsolete?
Why did my acceleration vanish one day?
Source & methodology
TCP window-delay model with RFC 1323 scaling; data-reduction factors from industry WAE deployment reports.
WAN Optimization: what this tool answers
This page was written for one job: turning your own inputs into a defensible figure, with the working shown. There are plenty of pages about WAN Optimization; almost none of them show the working. This one does: the formula, every input, a fully computed example, and a sensitivity analysis calculated live from this engine’s own defaults.
The number itself is the easy part. What takes judgement is knowing which inputs are facts in your situation and which are guesses wearing a decimal point — a distinction this page makes explicit for every field above.
In plain terms, WAN Optimization answers the question "Optimized transfer time?". The measurement matters because it converts a situation that feels complicated — several inputs pulling in different directions — into a single number you can act on. Within Technology & Computing, Networks & Storage is the context where this figure is quoted most often, and professionals treat it as a first-pass screen rather than a verdict.
Every figure in the prose is generated by the engine rather than written beside it — the worked example resolves to optimized transfer time = 11.4 min on the default inputs, and the sensitivity section ranks the inputs that move the result — WAN link first, at ≈11.1 % of the headline for a ten-percent error either way in that input. Read the sections in order and you will be able to reproduce every figure by hand.
How WAN Optimization is computed, line by line
Here is the complete model this tool runs — Proxy on ⇒ per-flow window 512 KB on LAN leg; transfer = GB×8192 Mb ÷ min(link, win/RTT) ÷ dedupe — with each input explained below. If a competitor’s page gives you a different answer from the same inputs, this is the text that settles which of you is right.
WAN link (Mbps) (example value 21) is a measured number in the unit named by the label; the formula does not convert for you. If you are unsure what belongs in this field, look at the printed steps: the substitution shows exactly how the engine uses it.
WAN RTT (ms) (example value 115) is a measured number in the unit named by the label; the formula does not convert for you. If you are unsure what belongs in this field, look at the printed steps: the substitution shows exactly how the engine uses it.
Typical transfer (GB) (example value 5) is a plain measured quantity — the unit shown in the label is the unit the formula expects. If you are unsure what belongs in this field, look at the printed steps: the substitution shows exactly how the engine uses it.
Dedup + compression effectiveness (example value 0) is a numeric input whose unit is fixed by the label; a wrong unit is a wrong answer wearing a plausible disguise. If you are unsure what belongs in this field, look at the printed steps: the substitution shows exactly how the engine uses it.
TCP proxy termination (example value On — LAN-speed ACKs + scaling) is a branching choice rather than a figure you measure; the per-option effects are computed below. Replace the example with the figure from your own records — the tool recomputes instantly and the printed steps follow your numbers.
What each “TCP proxy termination” choice actually does: Off — end-to-end TCP → 52.4 min · On — LAN-speed ACKs + scaling → 11.4 min These figures are computed from this engine, not estimated — switch the dropdown above and you will land on exactly these numbers.
A fully worked WAN Optimization example
Rather than describe the calculation, here it is end to end — every substitution in order, starting from the inputs above. Starting figures: WAN link (Mbps), WAN RTT (ms), Typical transfer (GB), Dedup + compression effectiveness. The computed optimized transfer time comes out at 11.4 min, which the interpretation band labels “Link is the new ceiling — appliance done its job”.
- End-to-end 64 KB window over 115 ms = 4.6 Mbps
- Proxy: 512 KB LAN-leg window = 21 Mbps, capped at 21 link
- Dedupe + compression moves only 35 % of bytes ⇒ ×2.9 effective
- 5 GB lands in 11.4 min vs 150 min raw
Raw transfer time (no proxy, no dedupe) — 149.7 min. Compare it against the main result of 11.4 min before drawing conclusions.
Acceleration factor — 13.2 ×. This is the number experienced users quote when the headline alone would mislead.
Effective goodput at appliance — 60.0 Mbps. Compare it against the main result of 11.4 min before drawing conclusions.
WAN bytes actually moved — 1,792.0 GB. This is the number experienced users quote when the headline alone would mislead.
Re-running with your own figures is instant; re-running by hand once is the best way to know the tool is telling you the truth.
How far WAN Optimization can reasonably move
The honest version of any estimate is a corridor, and this one is cheap to produce: WAN Optimization was recomputed at 5 points along the dominant input, with every other field left untouched.
| WAN link setting | Optimized transfer time |
|---|---|
| 80 % of the example value | 14.2 min |
| 90 % of the example value | 12.6 min |
| example inputs | 11.4 min |
| 110 % of the example value | 10.3 min |
| 120 % of the example value | 9.5 min |
Across 5 settings of WAN link, the result spans 9.5 min to 14.2 min. A decision that only works at one row of this table is a decision waiting for an input to move. Reproduce it in the form above by editing WAN link alone; the substitution steps will follow your figures exactly.
Where WAN Optimization is fragile — and where it is not
This list was computed for this specific engine just now: each numeric input was nudged ±10 % while every other field held its example value, and the optimized transfer time was recalculated from scratch. For WAN Optimization the ranking is measured rather than guessed, and it belongs to these defaults: shift the starting point and the order can shift with it.
- WAN link: ten percent up gives 10.3 min, ten percent down gives 12.6 min — ≈11.1 % of the optimized transfer time either way
- Nudge Typical transfer by ±10 % and WAN Optimization lands between 10.2 min and 12.5 min (sensitivity ≈10.0 %)
- Dedup + compression effectiveness: ten percent up gives 12.5 min, ten percent down gives 10.2 min — ≈10.0 % of the optimized transfer time either way
WAN link is the dominant lever here: ten percent either way moves the result by about 11.1 %, from 10.3 min to 12.6 min. Measure that input from a document rather than from memory, and treat Typical transfer as the second priority (≈10.0 % per ten percent). Everything below that can stay approximate, which is a licence to stop chasing data that would not change the decision.
Is your WAN Optimization good — reading the result bands
The value above only becomes useful the moment you know what it is being measured against. The verdict attached to the default calculation — “Link is the new ceiling — appliance done its job” — is one band on a ladder your own figure may sit somewhere else on. Before treating the band as fact, note its width: ten percent either way on WAN link already spans 10.3 min to 12.6 min. The practical reading rules: ask what would have to change to move you one band. If the answer is “a small, plausible input difference”, the band itself is not the finding — the uncertainty is.
Related measures answer related questions, and the distinctions matter: WAN Optimization is the quantity, Optimized transfer time is this tool’s reading of it, and the decision that follows belongs to neither of them separately.
The errors that quietly break a WAN Optimization figure
Dedupe ratios are workload-dependent: already-compressed media sees ~1.0×, while repeated branch file shares hit 5–10×; size appliances on your own mix. 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 WAN RTT (ms) while WAN link (Mbps) is still a guess. The sensitivity ranking above shows exactly where the accuracy budget should go.
One mistake is specific to this engine: assuming every input matters equally. The computation above shows WAN link dominating — a careful figure there beats false precision everywhere else.
The subtlest error is answering the wrong question precisely. Confirm that optimized transfer time is actually the quantity your decision needs — the arithmetic is flawless either way, which is what makes the mistake invisible.
A quick check for any WAN Optimization figure
- Compare the output against one published benchmark or a colleague’s independent estimate.
- Compare the result with one independent method or published benchmark.
- Check WAN link before anything else: it is the measured dominant input, ≈11.1 % of WAN Optimization per ten percent.
- Recompute once with the dominant input deliberately set low, and see whether the decision changes.
- Record the date and the inputs alongside the number so future-you knows what was assumed.
- Confirm the answer against one independent method or published benchmark for WAN Optimization.
Five steps from raw inputs to a figure you can defend
Using a calculator well sounds trivial, but the difference between a decision-grade figure and a throwaway one lives entirely in the routine. The routine for WAN Optimization takes a minute to learn and applies to every input above.
Step 1 — collect, then type. Everything this tool asks for is listed above (wan link (mbps), wan rtt (ms), typical transfer (gb), dedup + compression effectiveness, tcp proxy termination). Pull each figure from something you can point at — paperwork, a dashboard, a label — before touching a field. Guesswork at the input stage cannot be repaired at the interpretation stage. The fastest sanity test is to guess the answer first and see how far the calculation disagrees.
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. The input you reach for first is usually the one you measured longest ago.
Step 3 — isolate your variables. Change one field, observe, revert. The live sensitivity list does the ranking for the default inputs; verify it against your own, because dominance shifts when the starting point shifts. If the verdict changes with a ten-percent nudge, report the nudge alongside the number.
Step 4 — ask what would have to be true. Take the result you want and work backwards through the inputs until you find the assumption that produces it; then decide honestly whether that assumption is defensible. A figure with a date beside it becomes evidence; without one it stays an anecdote.
Step 5 — write the one-line memo. “Optimized transfer time = 11.4 min on this date, from these inputs.” That line is the entire deliverable; everything else on this page is how you earned the right to write it. The input you reach for first is usually the one you measured longest ago.
Where WAN Optimization matters in practice
Numbers earn their keep in conversations, and WAN Optimization is no exception. In Technology & Computing discussions around Networks & Storage, this figure decides whether an option stays on the table: it converts an opinionated debate into an arithmetic one, and arithmetic is the only referee both sides accept. A figure nobody can reproduce is a figure nobody will act on twice.
The companion outputs — Raw transfer time (no proxy, no dedupe) and Acceleration factor — exist for the second stage of that screen: the headline sizes the prize, while the companions describe the trade-off you are accepting to get it. The point of transparency is that a reader can disagree with a specific line rather than with you.
Re-running this page costs nothing and catches the slow drifts that never announce themselves. In Technology & Computing the expensive mistakes are rarely sudden; they are small changes in WAN link (Mbps) that nobody recalculated for a year. The inputs are the part of the work that nobody else can do for you.
The questions that come up most about WAN Optimization
What affects WAN Optimization the most?
WAN Optimization is driven above all by WAN link. Perturbing only that field by ten percent either way produced 10.3 min against the 11.4 min baseline — a ≈11.1 % response, while Typical transfer manages ≈10.0 %.
Which matters more: typical transfer or wan link?
By the numbers, WAN link: a ten-percent change in it moves the result ≈11.1 %, versus ≈10.0 % for Typical transfer. Spend your measuring effort in that order — precision on the weaker lever buys almost nothing.
How much does the “TCP proxy termination” choice change the answer?
The spread is not cosmetic: this choice alone takes WAN Optimization from 11.4 min to 52.4 min with every other input frozen, which is more influence than most of the numeric fields on this page can claim.
What is a typical WAN Optimization?
On the worked example above WAN Optimization comes out at 11.4 min. Treat that as one point on a distribution rather than a norm: the bands, the companion outputs and the sensitivity ranking tell you how wide the plausible range really is.
How do I calculate WAN Optimization by hand?
Proxy on ⇒ per-flow window 512 KB on LAN leg; transfer = GB×8192 Mb ÷ min(link, win/RTT) ÷ dedupe is the entire method. Work the inputs in that order — End-to-end 64 KB window over 115 ms = 4.6 Mbps — and you will reach 11.4 min on the default figures, the same number this tool prints.
What happens to WAN Optimization if wan link changes by 10 %?
Try it in the form above and the printed substitution will follow you; the pre-computed answer for the defaults is 10.3 min to 12.6 min across the ten-percent probe, i.e. ≈11.1 % sensitivity on the optimized transfer time.
Is the WAN Optimization result of 11.4 min good or bad?
The tool answers “what”, not “whether”: 11.4 min carries the verdict “Link is the new ceiling — appliance done its job” 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.
How do I calculate WAN Optimization manually?
Write down the inputs, then follow the printed steps in order — Proxy on ⇒ per-flow window 512 KB on LAN leg; transfer = GB×8192 Mb ÷ min(link, win/RTT) ÷ dedupe. A spreadsheet replicates it with two or three cells. The manual route is worth doing once to build intuition; after that the calculator saves time and eliminates transcription slips.
What affects WAN Optimization the most?
Sensitivity depends on where you start, but the inputs WAN link (Mbps) and WAN RTT (ms) typically move WAN Optimization further than the rest because they enter the formula multiplicatively. If you can only measure two things well, measure those and hold the others at conservative defaults.
Does QUIC make appliances obsolete?
QUIC dodges TCP bufferbloat but not byte volume or the last-mile link cap — dedupe and path shortening still pay.
Why did my acceleration vanish one day?
Cache invalidation: after a major version rollout or re-signing, dedupe stores miss until they refill — expect a temporary regression window.
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
- Raw transfer time (no proxy, no dedupe)
- 149.7 min for the WAN Optimization worked case; it sits next to the main result because it carries context the headline leaves out.
- Acceleration factor
- 13.2 × for the WAN Optimization worked case; it sits next to the main result because it carries context the headline leaves out.
- Effective goodput at appliance
- 60.0 Mbps in the default WAN Optimization calculation — one of the secondary figures an experienced reader checks before trusting the primary number.
- Optimized transfer time
- The primary output of this tool: 11.4 min for the default inputs, computed exactly from Proxy on ⇒ per-flow window 512 KB on LAN leg; transfer = GB×8192 Mb ÷ min(link, win/RTT) ÷ dedupe.
- Worked example
- Every substitution in order, from the example inputs to 11.4 min — the audit trail for the headline figure.
- Verdict band
- The plain-language label — here “Link is the new ceiling — appliance done its job” — mapping the computed figure onto experience-based ranges for Technology & Computing.
- Sensitivity (±10 %)
- How far the WAN Optimization moves when a single input is nudged ten percent either way; the ranked list on this page is computed live from this engine.
Where the WAN Optimization model comes from
There is no black box on this page — the engine evaluates Proxy on ⇒ per-flow window 512 KB on LAN leg; transfer = GB×8192 Mb ÷ min(link, win/RTT) ÷ dedupe. Source of record: TCP window-delay model with RFC 1323 scaling; data-reduction factors from industry WAE deployment reports. Specialist software layers extra coefficients on top of the same algebra; none are hidden here, and that transparency is what makes a disagreement traceable to a specific input instead of a black box.
Treat the output as a precise answer to the question you typed: exact arithmetic, transparent formula, published source, no hidden rounding. What that buys you is reproducibility — two people, two browsers, the same arithmetic, and a printed trail from inputs to result that either of them can audit.
Next steps after the calculation
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 Technology & Computing, a dated figure is a trend, and an undated one is a rumour.