The usual abbreviation for a thousand is "k" in AE, so "T" wouldn't work. Why not just use the number "100,000"?

Was ist mit 100 Mm oder 0.1 Gm?

Sorry, nur für "fortschrittliche" Autofahrer, die die Leistung ihres Motors in kWh angeben und kein Pferdegespann mehr vor der Motorhaube haben. ;-)

As far as I know, Tkm is neither a metric unit (it does look like tkm is used for "tonne kilometer," though) nor is it in common use, so saying that the readers are familiar with metric units isn't really of relevance here -- especially in light of dude's observation. It's also not a good practice to make up abbreviations, etc.

Is your phrase for a heading of a table or something?
If the phrase you need to translate is as given, "Required repairs up to" is 22 characters long, while "Erforderliche Reparaturen bis" is 29 characters, giving you seven "free" characters. "100 Tkm" has seven characters, "100,000 km" has ten characters. The English translation "Required repairs up to 100,000 km" is still shorter than the German you have presented.

Thank you for your comments!

The term I am looking for is needed in several situations, like in table headers, graphs and even for a user interface of an evaluation software. I can neither replace it by "000" nor by anything which uses miles, since the database is working with, well, "Tkm"s.

Looks like we are getting into some trouble with this...

There's no reason to replace metric units with English units in that, I'd say -- and that hasn't been suggested.

Unless things are set up in a very odd way, a table header shouldn't be restricted to having only a cryptic abbreviation. The user interface should be able to be localized appropriately (although it's highly likely that the German software engineer/program only allowed room for "Tkm" without considering that other languages may not use that...).

It appears, however, that you feel compelled to use Tkm in spite of getting the feedback that it isn't appropriate. A possible solution is to explain it in any area that has "regular" text and that makes reference to it -- such as "Required repairs up to 100,000 km ("Tkm")"

Well, let us say, the data entry clerk has a GUI box where he/she can enter "100", "200" etc., meaning "100,000 km", "200,000 km" etc., I need a label for this field indicating that the entered value is multiplied with 1,000 km.

The other case: I have a graph where one axis shows the numbers "100", "200" etc., again meaning "100,000 km" etc. I need an axis label for this.

Unless somebody comes up with a better suggestion I think I am going to use "1,000 km" as a label, hoping that, at least, "km" is being understood.

D'accord?

Ich habe schon öfters etwas wie "km'000" gesehen (zwar eher mit Währungssymbolen als mit km, aber das Prinzip funktioniert ja vielleicht trotzdem?).

Tachometers in the US use "rpm x 1000". Of course, that's an instruction in how to interpret the display of the tach (i.e. if you read 2.2, it's 2,200 rpm).

The labels could possibly be "km x 1,000" or "x 1,000 km"

I can assure you, if they know what a kilometer is, they'l know what "km" means in context.

To be clear, don't use Tkm, even as a defined term.

Stimme #9 zu und trage zu #2 nach.

Die englische Wiki kennt im Gegensatz zur deutschen das Megametre (Mm)
http://en.wikipedia.org/wiki/Megametre

Megametres (from the Greek words megas = big and metro = count/measure) are rarely seen in practical use, e.g. "5000 km" is much more common than "5 Mm".

Ich habe kein Problem mit "Tkm" = Tausend Kilometer, zumindest nicht, wenn es als Kürzel bei der Kennung von Spalten in Tabellen Verwendung findet. -

Rückblick: Banker benutzten zu D-Mark-Zeiten das Kürzel:

"TDM" = Tausend DM

Re: #11

"Tkm" may be fine from a German perspective, but it's obvious that NESs find it a bad choice. Also, currency abbreviations are different beasts than mixing a metric unit with a non-metric abbreviation (plus, I'd say that non-translated English would be less likely to use something like "TDM" than German does anyway).

leicht OT:
Re #11: Rückblick: Banker benutzten zu D-Mark-Zeiten das Kürzel:
"TDM" = Tausend DM

Eben! Und seit der Euro-Einführung wurde daraus der "TEURO" = Tausend EURO.
Als sie es denn bemerkten besann man sich der SI-Einheiten und schuf den "k€" oder "kEUR" ;-)

Say somewhere near the beginning that all distances are given in thousands of kilometres.

@#2:
Ich will doch nicht hoffen, das jemand versucht, die Leistung seines Motors in kWh anzugeben.

"Tkm" may be fine from a German perspective

Nein, das ist überall auf der Welt Unsinn. T ist das Präfix für Tera (10^12), das für tausend wäre k (in km ja bereits enthalten) und man kann nicht zwei Präfixe kombinieren. "Mm" (#10) wäre die einzig korrekte Form für 10^6 m, ist aber nicht gebräuchlich. (Komischerweise sind beim Meter die Präfixe für < 1 weit verbreitet (dm, cm, mm, µm, nm...), aber mit Ausnahme vom km nicht für > 1.)

@16: Those were my thoughts, which is while I formulated it using "may," but since I'm not a NGS I refrain from declaring what is "good" German.

/OT/
Re #15: Ich will doch nicht hoffen, das jemand versucht, die Leistung seines Motors in kWh anzugeben

Upps, erwischt - Freudsche Fehlleistung oder so. Ich will doch nicht hoffen, daß mein Stromanbieter versucht meinen Verbrauch demnächst in PSh abzurechnen ;-)

gaaaaaanz OT: Mal so von ing zu ing - ich habe deinen Nick immer falsch gelesen: ein-eing(ebildeter)

/TO/

Mal so von ing zu ing - ich habe deinen Nick immer falsch gelesen ...

Ich lese 'eineing' als 'Ein E-Ing.' ...

Let's face it, linguistically the metric system is a mess. We have a perfectly good word for the concept required, namely megametre, but we don't use it. We would have a perfectly good word for 1000 kilograms, but we say tonne rather than megagram. We have litres and hectolitres, but not kilolitre (= cubic metre). We talk about hectares, but a square kilometre is a square kilometre, not a megare. And we say we have 350 square metres of office space to let, not 3.5 ares. And Usain Bolt is tops in the 100 metres, not the hectometre. (And let's not forget the megadeaths that formed part of the vocabulary of Cold War strategists. At least we don't talk of the kilodeaths on our roads.)

escoville, you make it sound as bad as the English system! ;-)

Re #20:
Wenn euch die metrischen Megameter (Mm) als Wartungsintervall nicht gefallen, könnte man ja die Lichtmillisekunde (Lms) anziehen. Hier müssen wir allerdings mit dem Faktor 3 umrechnen.
http://en.wikipedia.org/wiki/Light-second

Erforderliche Reparaturen bis 300 Lms

The mean distance, over land, between opposite sides of the Earth is 66.8 light-milliseconds.

Dh. also ca. 2,2 mal um die Erde, dann Auto kaputt ;-)

Edith sieht gerade, daß die Interstate 90 ziemlich genau 5Mm lang ist
http://en.wikipedia.org/wiki/1_megametre
Also könnte das Wartungsintervall auch 20 I-90 sein.

I've driven much of I-90 many times. Traffic is often at a standstill in Chicago, and the unbroken flatness of many parts of it can be a killer. "Twenty I-90s" as a maintenance interval would be a killer if you had to actual drive the stretch...

The only technically correct (SI) solution would be to write Mm in both German and English, but given that the German version is using Tkm, how about kkm in English?

To return to my #20:

This morning on a BBC wildlife programme, one of the contributors talked of an area of '300 hectares'. I think both in Britain and in Germany only farmers talk in hectares, and I imagine 95% of listeners were, like me, totally incapable of visualizing 300 of them. However, at least I'm metrically numerate, and quickly calculated that 300 hectares is 3 million square metres, or (something visualizable at last), 3 square kilometres.