Document SE-CMP-001 · v1.0 · June 2026

Compare Calculators — Head‑to‑head

The Forge vs Easton, Hoyt, OnTarget!2, Archer’s Advantage — same arrow, same conditions, same numbers. By Sal Misseri.

I built this page because every archer I know has spent at least one afternoon entering the same arrow into three calculators and getting three answers. Sometimes the deltas are noise. Sometimes one of them is just wrong. This page puts The Forge next to the calculators it competes with, at one canonical setup, and shows the math next to the math. Where The Forge is better, I’ll say so. Where someone else is better — or where the right answer is “they all converge here, pick what’s in front of you” — I’ll say that too.

The Methods page (/pages/methods) is where I show how The Forge’s engine works. This page is where I show how it stacks up. The version history (/pages/version-history) is where I document every bug we’ve fixed in our own model — including the density-altitude unit-conversion fix that two of these competitors don’t even surface in the input form. I want to keep it honest. If you find a number on this page that’s wrong, write to sal@sparrowexpeditions.com.

0 ·Canonical setup

Every comparison on this page uses the same input set. If you change inputs, the deltas shift — that’s the nature of ballistics — but the relative positions of the tools hold. The setup below is the modern hunting compound an archer is most likely to be shooting at the moment: a top‑tier flagship at canonical 70 lb / 29″.

Velocity is the conservative end of what published RX-9 Ultra reviews chronograph at this draw and arrow weight (Outdoor Life measured 308 fps at 381.5 gr; Born Hunting at 80 lb / 425 gr saw ~325 fps). At 470 gr the regression lands at ~289 fps. This is the Podium-calibrated number The Forge uses for the RX-9 Ultra row in the bow database; it’s not optimistic.

1 ·Pin gaps at hunting distances (20–60 yd)

This is where most archers care most. You sight in at 20, and you want to know how the rest of the pins stack — how far apart they sit on the sight scale, what the gap between 40 and 50 looks like in real units. At a 4″ peep-to-pin radius the gaps below are what The Forge prints from its sight tape engine for the canonical setup.

What the row says. Hoyt and Easton don’t answer this question at all — Hoyt explicitly defers to Easton for arrow selection (Hoyt FAQ), and Easton publishes a spine chart, a FOC calculator, and a muzzle-only KE calculator. Neither company ships a sight tape or pin-gap tool. OnTarget!2 (Pinwheel Software’s SFAX) and Archer’s Advantage both solve this geometry from peep-to-pin and a trajectory model — the asterisks above mark “tool computes this; no public reference number at our exact input.” Both are paid (OT2 desktop ~$45, AA online ~$12/yr) so I can’t print numbers I haven’t verified myself. Verdict: at this distance band Easton and Hoyt aren’t competing; OT2 and AA both produce the same kind of answer The Forge does; the head-to-head that matters is “does the geometry match within sight-tape resolution” — which a user can verify in a single afternoon at the range.

Why a 0.109″ span at 4″ peep is the right answer here

The geometry is straight: pin offset = peep-radius × tan(sight-angle), and sight-angle is determined by the trajectory drop at that distance. Drop at 289 fps for a 471 gr arrow with the FMJ 5mm 340’s drag coefficient is well within the range published by Easton, Pelegrin, and McCoy for this class of arrow. The Forge integrates the trajectory numerically (RK4 over 200 steps), applies a documented BC-from-geometry estimator (Methods §3), and reads the sight angle at each distance directly. The result is a pin span that matches what an archer with a digital caliper would measure off a printed sight tape. If OT2 disagrees at the third decimal, the difference is almost certainly the choice of drag model — not a bug. If OT2 disagrees at the second decimal, one of us has something to check.

2 ·Sight tape — sliders, rotators, indicator deltas

If your sight slides (HHA Tetra, CBE Engage, UV3, Axcel AccuTouch), what matters is not the offset at each yardage but the indicator delta from one distance to the next at a chosen reference. The Forge prints this directly in the Pin Layout panel (shipped v128). Reference yardage = 20 yd; deltas below are the sliding distance from the 20-yd indicator position.

Where OT2 and AA are genuinely good. Both tools have a sight-tape feature that lets you enter two real shot positions (say, 20 and 60) and back-solve for the drag coefficient that reconciles them. That’s a useful calibration loop: it bypasses BC estimation entirely and gives you a tape that’s correct for your arrow at your bow at that day’s conditions. The Forge doesn’t do this yet — we solve forward from a BC estimate. If you have real chrono data and a known good sight mark at 60+ yd, AA’s Calculate Speed method is the cleanest tape calibration on offer. Credit where it’s due (AA setup docs).

3 ·Trajectory at 100 yd — where atmospherics matter most

Trajectory at long range is where DA, altitude, and temperature stop being curiosities and start being inches. The Forge solves for arrow drop including a documented density-altitude correction (Methods §5). Easton, Hoyt, OT2, and Archer’s Advantage all handle this differently. Below is the comparison at 100 yd at ISA sea-level standard. The right column — the same shot at DA = 7,500 ft — is where the calculators diverge.

The DA column is the whole point of this section. At 7,500 ft DA — a real Colorado late-September elk hunt — air density drops about 21% vs ISA sea level, drag drops with it, and the arrow at 100 yd falls 14″ less than the sea-level tape predicts. The Forge surfaces this in the Shot Solver (shipped v101) and corrects the sight-tape print accordingly. OT2 and AA both produce trajectory tables, but neither vendor publishes a density-altitude input field or an atmospheric correction methodology that I can verify. If yours does and I missed it, write to sal@sparrowexpeditions.com and I’ll correct this page.

Reversal noted on this page. The Forge’s DA formula shipped in v109 with a unit-conversion bug — we were applying 120 ft/°C to a °F delta, doubling the temperature contribution. Fixed in the same release after Sal caught it in QA. The number above is the correct one (66.7 ft/°F per FAA Pilot’s Handbook ch. 12). I’m showing the bug here because the credibility of a comparison page depends on owning our own mistakes; the version history is where every one is documented.

Trajectory plot — Forge sea level vs Forge DA 7,500 ft

4 ·KE, momentum, FOC — where calculators converge

This is the row where everyone agrees, because the formulas are simple, the conventions are standard, and the inputs are unambiguous. Worth showing for completeness, and worth flagging that convergence is the right outcome here — if a tool gives a wildly different number, it’s wrong, not innovative.

Convergence is the headline. Easton’s FOC calculator at (arrow length, balance point), Easton’s muzzle KE calculator at (weight, velocity), and Easton’s spine chart at (draw weight, arrow length, point weight) all give the same answers The Forge gives, because the underlying formulas are unambiguous. Easton’s spine selector is the right benchmark to validate any spine-recommending tool against. We do; they publish their chart and we land in the same cell. Where The Forge extends past Easton is downrange KE (40/60 yd) and momentum — Easton’s calculators stop at the muzzle.

5 ·What The Forge does that nobody else does

Some of what The Forge ships is in the comparison table above. Some of it isn’t, because no other tool produces an equivalent output. These features aren’t a fair head-to-head — they’re reasons The Forge exists in the first place. Flagged separately so they don’t turn into “we’re better at X.”

6 ·What we don’t compare (and why)

Three honest limitations on this page.

OT2 and AA are paid software. I can describe their published methodology and cite forum/review evidence of their outputs, but I’m not going to put numbers in their columns that I haven’t verified myself. If you own a license and want to run the canonical input set above and email me the outputs, I’ll publish them here with attribution. Until then, “computed” in the table means “the tool produces this kind of output; the specific value isn’t a public number we can cite.”

Hoyt’s “arrow calculator” doesn’t exist. Hoyt.com offers a Bow Builder (price + bow weight), tune-chart PDFs (cam/draw-length mechanics), and an arrow FAQ that defers all spine selection to Easton. There’s no Hoyt-produced spine, velocity, KE, sight tape, or trajectory tool to compare against. That’s an honest “no tool” row, not a snub.

The numbers on this page are for one canonical setup. They aren’t the right numbers for your bow. They’re a basis for comparison. The Forge is at /pages/the-forge — plug your own setup in and read your own numbers.

7 ·Sources

• Easton Hunting Arrow Shaft Selection Chart, doc 301055-A (Aug 2023): PDF
• Easton FOC calculator: eastonarchery.com/foc-calculator/
• Easton Kinetic Energy calculator: eastonarchery.com/kinetic-energy/
• Easton Shaft Selector landing: eastonarchery.com/selector/
• Hoyt arrow FAQ (defers to Easton): hoyt.com/frequently-asked-questions/arrows
• Hoyt RX-9 Ultra tune charts (cam/DL mechanics): hoyt.com/tune-charts/Hunting
• Hoyt RX-9 Ultra draw-length chart: hoyt.com/pages/carbon-rx-9-ultra-draw-length-chart
• Outdoor Life RX-9 Ultra chrono review (308 fps at 381.5 gr): outdoorlife.com
• Born Hunting RX-9 Ultra test (80 lb / 425 gr / ~325 fps): bornhunting.com
• OnTarget!2 / SFAX (Pinwheel Software): pinwheelsoftware.com
• Archer’s Advantage online: archersadvantage.com
• Archer’s Advantage setup & sight-in methodology: setup docs
• The Forge methodology & engine notes: /pages/methods
• The Forge version history & bug log: /pages/version-history